Cynodon dactylon

Cynodon dactylon

Bermuda Grass

It’s November in a very dry year which was preceded by a dry year. Most native plants are waiting for the rains. The small amount of rain that fell in the last week in October I doubt will be considered significant, i.e., sufficient enough to initiate plant growth. So Bonnie and I have punted on the selection of the plant profiled in this issue of the Obispoensis. We have chosen to make a scan of an all too common grass which is generally known as Bermuda grass, Cynodon dactylon.

According to Wikipedia, it has lots of common names in many different languages. Gardeners often refer to it as devil grass when in mixed company. I suspect they use more colorful language when they are trying to eliminate it from their lawns and gardens. The common name, Bermuda grass, reminds us not to depend on names to give us accurate information. Yes, Bermuda grass does grow in Bermuda, but it also grows throughout the warmer parts of the world. It grows on every continent that has areas where periods of low temperatures are rare or of very short duration. In the U.S. it is found in almost every one of the lower 48 states. It is especially common in the warmer half of the country.

Where does Bermuda grass come from if not Bermuda? It has at least three other wild varieties and all of them, including the wide-spread variety, Cynodon dactylon var. dactylon, are found in South-East Africa. Only C. d. var. dactylon has a worldwide distribution.

It was probably introduced to the U.S. in the 18th century, whether as a lawn grass or for forage crop is not clear. The species is able to survive long periods of drought by simply “dying back” to its extensive net-like system of rhizomes (horizontal underground stems). Aerial shoots can arise from any of its multitude of nodes (region of stems that produce leaves and buds). It is this capability to form long and extensively branched rhizomes that explains its use as a lawn grass. However, its weakness is its habit dying back during drought. This means that one’s nice green lawn will have brown spots or, if a Bermuda grass lawn, turn completely brown during the dry season.

Bermuda grass also doesn’t share an area well — it is extremely aggressive. In experiments where Bermuda grass is grown with various other herbaceous species, it inhibits the other species. In some cases Bermuda grass growth is better when paired with other species than when it grows alone. Needless to add, its aggressive growth is why gardeners refer to it as devil grass.

Where there is adequate water, Bermuda grass puts much of its growth into its green aerial shoots which makes it an almost great pasture grass. Why “almost great?” It is because, under some environmental conditions, livestock poisoning has been traced to it. The species is a prolific pollen producer so it is a major cause of discomfort by allergy and asthma sufferers.

I hope it goes without saying that Bermuda grass is not a California native and must be considered a noxious weed! It is most common in disturbed, vacant lots and poorly maintained lawns throughout the human dominated portions of our chapter area. It can also be found on roadsides and dryer edges of streams and salt marshes or wherever woody plants are widely scattered. It does seem to behave itself because it doesn’t seem to compete against trees and shrubs very well. It does not spread into native plant areas as it is intolerant of shade.

The scientific name, Cynodon, is derived from Greek and means “dog tooth.” The dog teeth are the distinctive small scale-like leaves that arise from the nodes of the rhizomes. Dactylon is also from Greek and refers to finger- like structures. In this case it refers to the usually 4 or 5 thin inflorescence branches which somewhat resemble the fingers of a human hand with the fingers widely separated.

by Dirk Walters, illustrations by Bonnie Walters | Dirk and Bonnie Walters are long-time CNPS-SLO members, contributors, and board/committee participants. In addition to his work at Cal Poly, Dirk is the current CNPS-SLO Historian.
Dendromecon rigida

Dendromecon rigida

Bush Poppy

A funny thing happened while Bonnie and I were working on the drawing and article for and about the plant discussed in this issue of Obispoensis. Before we started, we consulted Dirk’s list of past drawings and could not find any entry for Bush Poppy, a.k.a., Tree Poppy, (Dendromecon rigida). But after Bonnie was well into the drawing and I had started the article, we discovered a drawing and article from April 1995. We decided to go ahead and complete the ‘new’ drawing and possibly update what was said about Dendromecon back in 1995.

Bush poppy is one of the more common and easily recognized of our local shrubs. It is a woody member of the poppy family (Papaveraceae) and is especially common in our scrub communities (chaparral & coastal scrub) after fires. I’ve observed scores if not hundreds of plants per acre the first year after a fire. However, as the community matures, bush poppies begin to die out and become restricted to disturbed areas such as road cuts and trail edges. It is for this reason as well as its large conspicuous yellow flowers that this species actually appears to be more common than it actually is.

The poppy family is characterized by sepals being shed when the four petals expand (caduceus). Note that the spherical structures in Bonnie’s drawings are flower buds and not fruits. The superior ovary is long and thin. There are two very short styles which end in two large, flat stigmas. These can be seen in the drawing of the flower as well as the small aborting fruit found among the leaves in the 1995 drawing.

The ovary contains many seeds which are attached to two areas on opposite sides of a single cavity (i.e., parietal placentation). Each small seed contains a small fleshy body near the attachment of the stalk (funiculus) attaching it to the ovary/fruit wall. In the process of the capsule explosively splitting from the bottom up, the seeds are thrown away from the plant. After the seeds land on the ground, ants collect the attached fleshy body (aril) and carry them back to their nests. When the ants arrive back at the nest they either remove the seed from the aril before taking the aril into the nest or later. If the seed is removed later, it is taken out of the nest and thrown into the ant colony’s refuse heap. Either way, ants are very important in seed dispersal of this poppy.

Our local species is Dendromecon rigida which is common throughout most of the southern California mainland extending in to northern Mexico. A second species that is very similar to D. rigida is found naturally restricted to a few of the Channel Islands. This is D. hartfordii or the Channel Island tree poppy. This rare species differs from the more common mainland tree poppy by having larger flowers and shorter, fatter leaves. Lastly, the mainland tree poppy has minutely toothed leaf margins where as the island form has completely smooth margins. It appears that I may have misidentified the species in Bonnie’s 1995 drawing as the twig in the drawing as its leaves are drawn shorter and wider than her current drawing which is based on local SLO County plants.

One might expect that a plant with such large and showy flowers would have a significant following among California native plant aficionados. Also, we would expect the island bush poppy to be the preferred species as it has larger flowers, and this is often the case. However, Dendromecon is not commonly found in the home garden because it is particularly devilishly hard to get started. According to internet entries as well as Bornstein, Fross and O’Brien’s California Native Plants for the Garden (2005), its roots are especially sensitive to disturbance. According to Dara E. Emery’s book, Seed Propagation of Native California Plants, growing it from seed requires either a fire treatment or stratification (buried in between layers of moist sand) for 1½ months with a daily temperature fluctuation of between 46oF and 70oF. Mr. Emery indicates they can be more easily propagated by winter cuttings placed in a propagation bench supplied with intermittent mist and bottom heat. If you do try to propagate this species or especially if you buy potted ones, remember to treat their roots with extreme caution. Plant the root ball with little or better NO disturbance.

by Dirk Walters, illustrations by Bonnie Walters | Dirk and Bonnie Walters are long-time CNPS-SLO members, contributors, and board/committee participants. In addition to his work at Cal Poly, Dirk is the current CNPS-SLO Historian.

Silene laciniata

Coastal catchfly

Late summer or early fall (or more appropriately “late dry season”) is a downtime in our local wilds, especially true when we’ve had no significant rain after December. Even the animals seem to be resting. But if one looks carefully in our coastal dune scrub, one may just see a FEW bright red flowers commonly called Indian Pink around here. Indian Pink is also the name in RF Hoover’s book Vascular Plants of San Luis Obispo County. I found a better common name on the internet, Cardinal Catchfly. Either way it’s Silene laciniata.

Since it has very weak stems, Silene laciniata has the habit of using other plants for support. Look for it growing out of the canopies of relatively short plants. Our chapter area is near the northern extent of this species range; it can be found on our coastal dunes and further inland on serpentine outcrops. Its usually hidden, paired leaves are broadly joined at their bases and appear, at first glance, to be quite grass-like. But no grass has opposite leaves and a close examination of the leaf blades will show a single, larger midrib.

Coastal catchfly (Silene laciniata)

Coastal catchfly (Silene laciniata)

An examination of Bonnie’s drawing shows what appear to be the five fused petals at the end of a long tube. The tube is formed by the fused sepals (calyx). The petals are actually separate. If one were to slit down the side of the calyx tube, the five separate petals would simply fall away from each other.

Each petal consists of two quite distinct regions. The showy part is bright red and is called by botanists “the blade.” Each thin basal portion, called “the claw” by botanists, is the length of the tube and basally attaches separately to the receptacle below the ovary. The sepals and stamens also attach to the receptacle. So, in spite of casual appearance, the ovary is superior.

The local common name, Indian Pink, I believe to be the less desirable today because of the use of “Indian.” The name, Indian, often indicates that the plant in question was used in some way by the native North American peoples. I didn’t find any reference to their use of this species either on line or in my library. I’m guessing that the use of the word, “Indian,” here simply refers to it being native to California.

The second name, Pink, refers to a common trait in its family, Caryophyllaceae, or pink family. Pink, in this case, does not refer to the flower’s color, which is bright red, but to the fringed petals. That is, it refers to the tailors’ practice of cutting the edge of unsewn fabric with pinking shears to leave it toothed to prevent it from unraveling. Now Cardinal Catchfly is a much better name.

First, the flowers are bright red like the plumage of a cardinal. The term, catchfly, refers to a common trait found in many flowers that produce many special trichomes (hairs) on their sepals. These individual trichomes resemble the colored pins often used to stick into maps; they have short shafts and large round heads. When mature, these “heads” break down into an acrid, terrible tasting glob that is sticky enough to ensnare small insects such as flies and bees.

Why would this be an advantage to the flower? Many flower visiting insects, when prevented from entering the flower the correct way will attempt to steal nectar by biting a hole through the base of the flower or calyx. This is pure thievery as the insect gets the costly nectar without pollinating the flower.

How might a Cardinal Catchfly be pollinated? First thing we need to do is note that the only possible (legal) entrance to the deep, relatively narrow floral tube (where the nectar is produced at its base) is via a very tiny hole through which the style and stamen filaments emerge. So a pollinator would have to be either small enough to enter the hole (not likely) or have a very long, thin proboscis or tongue. That eliminates essentially all flies, bees and beetles, which have short chewing mouth parts.

That leaves three common long-proboscis pollinators – butterflies, moths and hummingbirds. Butterflies usually require flowers that provide a landing platform. The Cardinal Catchfly is orientated so that the showy parts (blades) of the petals are vertical, which does not provide a landing platform for butterflies. Cardinal Catchfly blooms during the day so that should eliminate most moths.

Further, I haven’t noticed any pronounced floral odors produced by this flower. A day-flying pollinator that hovers in front of the flower, possesses a long, thin beak (and tongue), and with keen eyesight in the red portion of the spectrum would be a humming bird. In addition, birds tend to have little sense of smell. It’s a conclusion that could have been gotten easily from the internet, but not nearly as fun.

by Dirk Walters, illustrations by Bonnie Walters | Dirk and Bonnie Walters are long-time CNPS-SLO members, contributors, and board/committee participants. In addition to his work at Cal Poly, Dirk is the current CNPS-SLO Historian.

Calystegia macrostegia

Coastal Morning Glory (California)

The plant featured on the June 2013 cover of the Obispoensis was chosen because of a request. It is the California, coast, island, or wild morning glory (Calystegia macrostegia).

The common name, false bindweed, is sometimes used instead of morning glory. Bind weed and morning glory are often used interchangeably. This species was chosen because of a request by CNPS member Yolanda Waddell who asked some time ago about the plant. Bonnie and I encourage anyone to email, write, or even call us with comments or questions about the drawings or articles or both. After doing this since the mid 1970’s, we especially like to receive suggestions for native plants that others might find interesting.

Plants called morning glories generally produce large flowers with five fused petals arranged in the shape of funnel. Bindweeds generally have smaller flowers. The morning glory common name refers to the fact that individual flowers tend to open in the morning and close by the same afternoon. Most of the time the flowers are basically white, but they may have pale pink veins. As the flowers age, they may take on a pinkish tinge.

There are at least two possible explanations for color changes in flowers. First is that it is caused merely by the aging and dying of the petal’s cells and has no survival value. However, there is a second possible explanation. It has been documented that some flower color change is controlled by the flower in order to signal its pollinator that this flower has been visited already so don’t waste your time visiting me.

Why would a plant do this? If pollinators visit only unpollinated flowers, then the pollinators will visit more flowers because they will visit only those flowers still requiring a pollinating visit. Is the color change in morning glory ecologically significant? I don’t actually know, but it would be interesting to find out.

Let’s look at Bonnie’s drawing. It shows a single twining stem. Note how thin the stem is drawn; it’s less than oneeighth inch in diameter. From each leaf bud a stalked 1-3 inch flower or pair of flowers arises. This means they are widely spaced along the individual stem. But, in the field, morning glory stems are rarely found single. A given rootstock produces many stems that will start out growing side by side, and because they twine they wrap around each other forming a structure similar to a braided rope. Since each individual stem is producing flowers, a given length of “rope” produces many flowers that appear to be growing side by side.

Not only that, morning glory plants may cover large areas. When this happens, the “ropes” criss-cross to form a net. The flowers then appear be arising from a mat. Because of this, most photos are distant shots of the mat and therefore don’t show the details of the stem. Some books indicate that the stems of this species of morning glory are somewhat woody at the base. To be truthful, I’ve never looked for this because one is totally overwhelmed by the mat of herbaceous “ropes.”

Leaves in this morning glory are extremely variable in size. On new stems leaves may be only an inch or so long but at other times they can grow to be nearly six inches long. Leaves are triangular with two prominent lobes at the base.

Calystegia macrostegia is an extremely variable species. The most recent Jepson Manual recognizes six subspecies throughout its range which runs mostly along the coast from just north of the Bay Area to just south of the Mexican border. There are also subspecies on the Channel Islands. Therefore this morning glory is almost an endemic Californian, i.e., restricted to the state. The subspecies to be expected in our area would be C. m. ssp. cyclostegia. Since this subspecies is found almost exclusively on the mainland, I think the best common name for it would be California morning glory or even better California coastal morning glory.

There are three genera that typically bear the morning glory common name. They are Calystegia, Convolvulus, and Ipomoea. Ipomoea is native to the old world and is the genus of garden morning glories. In older plant ID books, species now separated into Calystegia and Convolvulus were all included the genus Convolvulus. Currently these two genera are separated most easily on the size and location of two bracts that are attached to the flower stalk.

In Calystegia, the bracts are large and totally hide the calyx. [Caly = calyx or sepals and stegia = Greek meaning to hide]. Macrostegia refers to the fact that the hiding bracts are large (macro).

In Convolvulus, the tiny scale-like bracts arise from near the middle of the flower stalk.

by Dirk Walters, illustrations by Bonnie Walters | Dirk and Bonnie Walters are long-time CNPS-SLO members, contributors, and board/committee participants. In addition to his work at Cal Poly, Dirk is the current CNPS-SLO Historian.
Fremontodendron californicum

Fremontodendron californicum

Flannel Bush

This month’s cover drawing by Bonnie Walters is a repeat of flannel bush, Fremontodendron californicum. It was last used on the Obispoensis cover back in 1991. Does anybody remember it?

Fremontodendron classification

It is being reused now due to a request Bonnie received to use some of her drawings for a project associated with “Learning among the Oaks” program. Of course, this required us to go back into our archives to find it. Also, it was obvious to us that the write-up that accompanied the earlier cover was clearly out of date. Back then the article stated that flannel bush was “a member of the moderately large (65 general and 1000 species) and predominantly tropical family, Sterculiaceae. The most famous member of this family by far is cacao, Theobroma cacao, the plant from which from which chocolate is made.”

Today we have to accept the conclusion that flannel bushes are part of the large (266 genera & 4025 species), cosmopolitan (but still favoring warmer regions of the earth) Malvaceae. This family is most often called the cotton, hibiscus or mallow, and obviously chocolate family. The most obvious characteristic shared by flannel bush and the rest of the Malvaceae is the fusion of their stamen filaments into a tube that completely surrounds and thus hides the ovary and style base. One other note, the beautiful yellow perianth elements found on flannel bushes are sepals not petals; Fremontodendron does not have petals. This is because there is only one whorl of perianth and when that happens, botanists almost always define them as sepals.

Back in 1991, it was noted that Fremontodendron in California had only two species – F. mexicanum and F. californicum. In 2013 we have to acknowledge that there are now three recognized species. A new species with a very restricted range (found only in Yuba & Nevada Counties) has been separated from F. californicum. This new species is F. decumbens or the Pine Hill flannel bush.

Growth Habit

Unlike the other species which are erect, small trees or large shrubs, Pine Hill flannel bush grows flat on the ground. The new Jepson Manual indicates that this species is “morphologically, genetically” distinct (i.e. looks different and doesn’t cross with) from the other species.

Use in the Garden

As one might guess because of its large flowers, flannel bushes ought to be sought after as horticultural plants. The problem is that they are considered hard to grow. They require well drained soils with little summer water. If one tries to plant them in clay, such as found around San Luis Obispo, one internet reference recommended digging a large hole (three feet across and deep) and filling it with sand before planting. This will keep the soil in contact with the root crown from prolonged contact with moist soil. Summer watering (after establishment) and/or moist soil in contact with the root crown will kill it in a couple of years.

The pure species in cultivation is mostly F. mexicanum as it has the largest flowers. However, this species is restricted to extreme Southern California and adjacent Mexico. Because of this, gardeners have created hybrids and selections that combine the environmental latitude of F. californicum with the large flowers of F. mexicanum, thus making the hybrids much more garden friendly.

Gardeners on the internet stress that flannel bushes are large plants and don’t fit well into small suburban settings. They also noted that the pubescence (hairs) that shed from the twigs can be very irritating. Therefore, it might be best to plant it where people do not congregate.

Fremontodendron in the Wild

F. californica is found in desert washes and on dry, well drained foothill slopes. It is particularly common in the high desert and southern Sierra foothills where it prefers locations soil surfaces are habitually dry yet have available water from relatively shallow water tables. This is because their root crowns are particularly susceptible to various pathogenic fungi that live near the surface. It is these soil pathogens that make it difficult to maintain in cultivation.

Viewing Flannel Bush in SLO County

It can be found in our county in scattered colonies along the crest of the Santa Lucia Mountains and on a few of the higher peaks in the interior. The most accessible stand is just east of the forest service road to the Sergeant Cypress Grove on West Cuesta Ridge. Most of our plants have smaller, three-lobed leaves instead of the more common five-lobed leaves characteristic of the species. Because of this Dr. Robert Hoover named our local plants, F. californicum var. obispoense. I also think I remember Dr. Robert Rodin, a plant anatomist and morphologist, telling me that the flannel bushes on West Cuesta Ridge also had one less chromosome than the rest of the species. If this is true, it would further strengthen the separation of our plants into a distinct variety.

A Local Hybrid

I have one last note. A member of our chapter enters the story of producing a much more water-tolerant Fremontodendron garden. This cross, between Fremontodendron californicum and the tropical monkey’s hand tree (or Chiranthodendron pentadactylon) was being propagated for eventual release into the trade at Rancho Santa Ana by then Rancho graduate student and later SLO County Chapter member Austin Griffiths. At least one of these inter generic hybrid plants was planted on the Cal Poly campus. I do not know if it is still living there.

by Dirk Walters, illustrations by Bonnie Walters | Dirk and Bonnie Walters are long-time CNPS-SLO members, contributors, and board/committee participants. In addition to his work at Cal Poly, Dirk is the current CNPS-SLO Historian.
Asparagus asparagoides

Asparagus asparagoides

Asparagus Fern or Bridal Creeper

This month’s plant is a South Africa native that has become naturalized in Southern California where there has the potential to become an extremely troubling weed species. It is already considered so in some localities in Southern California, New Zealand and Australia. It had become a major infestation in the oak grove near Lupine Point in the Los Osos Elfin Forest until it was successfully removed after much effort.

The problem with its eradication is obvious from looking at the cluster of corms that form just under ground. If left to multiply, this corm mat forms an extensive, impenetrable mat just below the soil surface that prevents other plant roots from getting to the nutrients they require. A second problem with the corm cluster is that if one just goes out and attempts to pull them up or cut them down, the corms just send up new shoots. One would have to repeat the removal process until the corms have been starved to death. That would be a long arduous process.

The fast and extensive stem and leaf growth is also a problem. It allows the asparagus fern to cover existing plants so well that sunlight can’t get to them.

I asked Bonnie to draw the plant with flower buds only because plants currently available to us are at that stage. I suspect that, if deadlines weren’t a consideration, a plant with fully open flowers might have been found since its blooming period is from December through April. But more importantly, this species’ vegetative state is so distinctive that the smallish, nondescript flowers are often overlooked anyway.

A word of warning, written descriptions of this plant in many books are totally deceptive. First, what looks like leaves are in fact flattened stems, which botanists often term cladodes. Unfortunately I also ran across several other technical terms for them.

How does one know they are “flattened stems” and not what they actually look like – “leaves.” All vascular plants have the same leaf-stem morphology. First the stem is divided into alternating nodes where the leaves are attached and internodes where there are no leaves. The exterior nodal structure includes the leaf and a bud found in the upper angle between the leaf base and the stem. When the bud germinates it produces a new stem which then can produce more leaves. This means that a given portion of stem produces a leaf only once or leaves are produced only during the first year of that particular stem’s life.

Remember, buds produce new stems only. So a reexamination of Bonnie’s drawing shows the green flattened stems (cladodes) arising from the angle of a small grayish scale. That scale is all there is to the true leaf. Using flattened stems for leaves is considered an adaptation to drought conditions.

As an example of how confusing this can be, look at the identification keys in the New Jepson Manual. The keys from group to family to genus to species all assume that you know that the leaves are those tiny, insignificant, hardly visible scales under the things that everyone but a botanists would assume where leaves but aren’t.

Bonnie has drawn a couple of flower buds coming from the axil of leaf whose bud grew into the cladode. Examine the node again very carefully. You will note that there are actually three scales visible. The largest one is the leaf and the two smaller ones just visible are the bracts (leaves associated with flowers) whose buds germinated to produce the flowers. Botanists consider flowers to be highly modified leafy branches. Why they think this must be the subject for another time. Oh yes, that means this plant must produce 3 leaves and buds per node. Two of them only develop when that node produces flowers, otherwise they would be invisible.

The plant has a number of common names as might be expected of a plant used by humans. Its primary use is in floral arranging. Its thin stem and abundant dark green cladodes together give it a kind of filmy or ferny appearance which explains the “asparagus fern” name.

Its long use in bridal bouquets explains its African bridal creeper, bridal-veil creeper, or merely bridal creeper names. Other names that I’ve seen include Gnarboola, Smilax or Smilax asparagus. The last two names should be forgotten as they indicate it is related to the genus, Smilax, which it is not. I assume Gnarboola is its name in its native Southern Africa. The genus, Asparagus, belongs to a group of monocots that produce flowers with a perianth of six sterile elements that are more commonly called sepals and petals.

This genus’ flowers have 3 greenish-white sepals and 3 identical greenish white petals. When sepals and petals are identical except for position (sepals are always the outer whorl and petals interior to the sepals) botanists use the term “tepals.” There is a large assembly of tepal plants including the lilies, amaryllis, tulips, onions, and garden asparagus. The list could go on and on. The problem with this group is that all their flowers are built on the same plan and whenever this happens taxonomist often can’t agree on family or even ordinal boundaries. For example, a search on my library and internet finds this genus placed in the lily family (Liliaceae – order Liliales) or the Asparagus family (Asparagaceae – Asparagales). Added to this the current distinction between these orders has to do with different DNA sequences and unique chemical constituents found in their seed coats, neither of which are hardly field characters. For the record, the new Jepson Manual puts this plant in the Asparagales and the Asparagaceae.

by Dirk Walters, illustrations by Bonnie Walters | Dirk and Bonnie Walters are long-time CNPS-SLO members, contributors, and board/committee participants. In addition to his work at Cal Poly, Dirk is the current CNPS-SLO Historian.
Amanita phalloides

Amanita phalloides

Why is the Death Cap mushroom so deadly?

On New Year’s Day I visited a favorite, and normally productive, chanterelle patch outside San Luis Obispo to discover an enormous fruiting of the dangerously toxic death cap mushroom (Amanita phalloides).

My culinary disappointment was tempered by my growing fascination with the question, “Why are mushrooms deadly poisonous?” Proximally, the answer is direct: because they contain a peptide, alpha-amanitin, which halts RNA transcription in the cell nucleus. In broader context, the question should be rephrased, “What ecological advantage and evolutionary fitness does the presence of this toxin contribute?”

Amanita phalloides is a newcomer to California. It is known to be a native of Europe, and its first verified collection in California dates to 1938. Anecdotally, its introduction is ascribed to an accidental arrival on the roots of cork oak trees. It is now known from Southern California to British Columbia. A similar introduction (on the roots of Italian chestnuts?) affects the East Coast.

Death cap is an ectomycorrhizal symbiont. This means it forms connections on the root-tips of forest trees; in California, its typical (but not exclusive) partner is coast live oak. Unlike many symbionts which are highly host specific, death cap is promiscuous in its associations as it spreads worldwide. It is now present in South Africa, Australia and most other similar climes.

Ectomycorrhizal (EC) fungi collect major nutrients, nitrogen and phosphorous, and exchange these with the host tree for sugars. Delicate hyphal strands extend outward from the root tip mass into the surrounding soil and mulch. EC also allows efficient active transfer of macronutrients, micronutrients, and soil water to the tree. The chronic phosphorous limitation in serpentine soils makes the EC symbiosis especially important for local forest types on this soil. Studies in Norway discovered up to 50% of a birch tree’s sugar is exchanged at the root tips with EC symbionts.

Death Cap - Amanita phalloides

Death Cap – Amanita phalloides

Other studies describe how a mushroom, Laccaria bicolor, lures springtail insects (Folsoma candida) into traps, consumes them, and transfers the nitrogen obtained to its host tree.

Trees form non-exclusive associations with many fungi. Studies at Pt. Reyes show more than 15 taxa of EC fungi present at the root tips of coast live oak from a single grove. Most of the live oak symbionts are not deadly or even dangerous, and include the sought after chanterelles.

It is an entirely open research question as to whether the recent invasion of Amanita phalloides into the California oak forest is supplanting native fungi. Studies (in Bishop pine) have shown that EC fungi partition their habitat niches very precisely, allowing multiple fungi to coexist in close proximity. I have visited the particular chanterelle patch since the 1970’s without noticing the Aman5.0ita, so the 2012 fruiting might possibly represent a replacement of one symbiont for another, or just be a fortuitous fruiting of an established co-dominant.

The “competitive exclusion principle” argues that if these organisms are competing within the same precise niche, the most successful will replace all others. The deadly toxin of Amanita’s is alpha-amanitin. This is a heat-stable cyclic peptide that interferes with the transcription function of RNA in the nucleus of cells of virtually all organisms.

Humans, dogs, rabbits, and guinea pigs are equally poisoned. The toxic crisis is caused by irreversible liver or kidney damage, as the molecule concentrates in those organs. More expansively: organisms other than bacteria are affected by alpha-amanitin. Insects, worms, flowering plants, and even viroids (infectious single strands of RNA) that cause “mad cow” and disease in plants cannot replicate when treated with amanitin.

Amanitin is a large, very stable molecule (C39H54N10O14S) so it represents a significant metabolic cost to the fungus to create. Several, widely unrelated, taxa of gilled mushrooms possess amanitin toxin, so its synthesis has been separately evolved several times in fungi –supporting the assumption this represents an important competitive innovation for the species. Fortunately, amanitin is too large to cross the blood/brain barrier, so even victims with irreversible liver and kidney damage due to mushroom poisoning are not affected mentally.

An evolutionary entomologist working in New York State, John Jaenike, has discovered four species of mushroom flies in the genus Drosophila that lay eggs in the gills of fruiting Amanita phalloides. The fruit fly taxa are related to ones that inhabit rotting skunk cabbage, but in New England have recently transferred to the recently introduced Amanita fruitings.

Jaenike discovered that Amanita phalloides is toxic to the damaging parasitic nematodes Howardula that reproduce in the stomach of fruit flies. The toxicity of the death cap to the parasitic nematodes results in much greater egglaying (fecundity) by the fruit flies. The fruit flies are affected by the toxic amanitin, especially the males, but the poison is more than offset by the increase in reproduction.

Janike also discovered that most other insects using mushrooms as egg laying sites (craneflies and forest gnats) shun use of the Amanita (due to its toxicity).

Fruiting mushrooms are a scarce and erratically scattered resource for reproduction and larval feeding. Fruiting mushrooms are fully and completely consumed by mushroom gnat larvae, and Jaenike postulates fierce competition for insect breeding sites. Jaenike has published several papers describing the Amanita-Drosophila-Howardula food web. Mushroom flies secured a niche free of competition by exchanging an evolved tolerance to sub-lethal poisoning for escape from nematode parasitism. The increased fitness leads to greater egg-laying ability, and has provided the evolutionary inertia for this recent adaptation.

Nematodes are significant pests of commercial mushroom production, epidemic infestation can result in the loss of the growing beds. The oyster mushroom, Pleurotus osteraceus, traps and consumes nematodes in noose-like knots of hyphal tissue.

So why are Amanita so poisonous? It is an unlikely deterrence to vertebrate predation of the fruiting caps, as the effect is slow-acting (36-72 hours before the toxic crisis in humans) and the toxin is not concentrated in the cap. Evidence supports the hypothesis that the fitness obtained from synthesizing the toxin is secured within the hyphal network. Perhaps toxic Amanita obtain nitrogen from poisoned nematodes, or protect themselves (and their symbiont hosts) from plant parasitic nematode predation.

Perhaps the toxin suppresses the growth of competing fungal webs. It seems clear the toxic effect of death cap is intrinsic to its invasive success worldwide.

John Chesnut | Rare Plant Coordinator and Education Committee at CNPS-SLO, John teaches horticulture at Cal Poly

Sources:

Jaenike, J., “Parasite Pressure and the Evolution of Amanitin Tolerance in Drosophila,” Evolution,Vol. 39, No. 6 (Nov., 1985), pp. 1295-1301. Jaenike, J. and T J. C. Anderson, “Dynamics of Host-Parasite Interactions: The Drosophila-Howardula System,” Oikos Vol. 64, No. 3 (Sep., 1992), pp. 533-540. http://web.uvic.ca/~stevep/pdfs/AmNat_02.pdf

Pringle, Anne, and Else Vellinga, “Last chance to know? Using literature to explore the biogeography and invasion biology of the death cap mushroom Amanita phalloides.” http://www.msi.harvard.edu/downloads/teacherworkshop/Readings/Ben_Papers%20_TWS/Pringle%20and%20Vellinga%202006.pdf

Pringle, Anne, Rachel I. Adams, Hugh B. Cross, and Thomas D. Bruns, “The ectomycorrhizal fungus Amanita phalloides was introduced and is expanding its range on the west coast of North America,” Molecular Ecology (2009). http://arnarb.harvard.edu/faculty/pringle/pubs/Pringle_MolEcol_2009.pdf

Wolfe, Benjamin E., Franck Richard, Hugh B. Cross, and Anne Pringle, “Distribution and abundance of the introduced ectomycorrhizal fungus Amanita phalloides in North America,” New Phytologist (2009). http://www.oeb.harvard.edu/faculty/pringle/documents/Wolfe_Ap_Distribution.pdf

Wieland, Theodor and H. Faulstich. Amatoxins, Phallotoxins, Phallolysin, and Antamanide: The biologically Active Components of Poisonous Amanita Mushrooms. http://informahealthcare.com/doi/pdf/10.3109/10409237809149870

Horton, Thomas R., and Thomas D. Bruns, “The molecular revolution in ectomycorrhizal ecology: peeking into the black-box,” Molecular Ecology (2001)10, 1855–1871. http://www.cnr.berkeley.edu/brunslab/papers/

Quercus douglasii

Quercus douglasii

Blue Oak

Bonnie’s drawing on this cover of the Obispoensis includes an acorn, a couple of leaves and a two individual blue oak (Quercus douglasii) trees from Shell Creek.

This species of oak is extremely common in a vertical band through the center of our Chapter area. It is most common east of the Santa Lucia crest and west to the San Juan River drainage. It occurs only occasionally near the coast where it is replaced by the coast live oak (Q. agrifolia). In the Carrizo Plain area the Tucker oak (Q. john-tuckeri) replaces it.

Unique coloring

I suspect all of us who know the tree know it as blue oak. Its common name refers to its bluish green deciduous leaves and/or its pale gray bark. Other names I’ve found include iron oak, mountain white oak, or mountain oak. The light blue/gray color is particularly evident when compared to evergreen oaks such as liveoaks (Quercus agrifolia, interior live oak (Q. wislizeni) and gold cup oak (Q. chrysolepsis), all of which live within or near the blue oak range. But remember, both leaves and bark are quite variable in color based on where the tree grows.

Leaves and bark are lighter (i.e., more gray or blue when the tree grows in open groves on sunny south and west facing slopes and darker and greener where moisture is present such as north and east facing slopes).

Blue oaks prefer well drained soils so they tend to be found on foothill slopes surrounding California’s Central Valley. Yes, blue oak is endemic to California, which means that it is found naturally only within the political boundaries of California.

A great deal is known about the ecology of the blue oak. So much that it is difficult to chose what to emphasize in a general piece such as this. When I did a web search of Quercus douglasii a fantastic tell-all forest service website headed the list. The web address of this site is http://www.fs.fed.us/database/feis/plants/tree/quedou/all.html. One thing I will mention about the web site is that the small amount of stuff I knew already I noted was correct. This leads me to conclude that the vast amount of detail I didn’t know is also true.

Ground cover

One item worth mentioning is the ground cover of herbs Bonnie has drawn around the base of the oak trees. The species found in this area within the drip line of the tree’s canopy are quite different in composition and abundance from the species outside the drip line. Several hypotheses have been proposed for this phenomenon. First, the deep roots of the oak bring up nutrients from deep in the soil where they are below the reach of the shallower-rooted herbs. Because the leaves are a “leaky” system, some of the water soluble nutrients get deposited on the surface of the leaves where they are washed off and drop to the soil under the tree. It has also been noted that during the hot parts of the day, cattle seek shade under the trees. While there, they deposit undigested or unabsorbed nutrients under the tree. Either way, it is hypothesized that there is higher nutrient availability under the tree’s canopy than outside it.

Blue Oak and California native ethno-botany

I will make just a quick note on native California peoples use of the blue oak acorns. All writers discussing California native ethno-botany acknowledge that acorns of this species and most other oak species were gathered and used. In a list of acorns used by the Native Californians that I found on the internet, blue oak tops the list. Essentially all references refer to it as producing the “sweetest” acorn. I assume that means it has the best flavor, which should mean it has the lowest tannin content. Tannins are complex chemicals that are not only bitter tasting, but also interfere with digestion by creating blockages in the digestive tract.

Since tannins are water soluble, they are removed by leaching. Native Californians usually leached acorn meal by placing it in a basket and then placing the basket in running water. I’ve heard people ask where they found the water for all the required leaching. Today, if one wants to eat acorns, one must use treated tap water. That would prove to be quite expensive. One must remember that pre-European Native California populations were relatively small and scattered. There was no Mexican- or European-style field agriculture (except within the Colorado River Valley) in California.

There was habitat manipulation as was discussed by our recent banquet speaker, Kat Anderson, but the smaller population and low impact vegetation manipulation would mean that most streams would flow longer into the dry season and be less polluted than we no find them today. They could simply have been able to put their acorn meal filled baskets into any nearby water course with no ill effect.

by Dirk Walters, illustrations by Bonnie Walters | Dirk and Bonnie Walters are long-time CNPS-SLO members, contributors, and board/committee participants. In addition to his work at Cal Poly, Dirk is the current CNPS-SLO Historian.
Polypodium californicum

Polypodium californicum

Common Polypody or California Polypody

Bonnie’s drawing this time represents a fern recently found in the Los Osos Elfin Forest. The fern is the common or California polypody (Polypodium californicum). It was found by Al Normadin while scouting for his recently led trip in the Elfin Forest. It is a quite common and widespread fern on the Central Coast, where it is commonly found growing along edges or out of cracks in rocks. It is especially common on north facing slopes.

However, I was surprised to find it reported from the Elfin Forest. This is because ferns generally require consistently available soil moisture. Since the Elfin Forest Reserve’s sandy soils tend to lose their moisture and it doesn’t rain for over six months, one would not expect to find many fern species here. I suspect these particular ferns are able to do so because they occur in shade near or under the pygmy oak over-story where the oaks provide shade and extra moisture. The extra moisture comes from the ability of the pygmy oaks to condense water on their leaves and twigs from the common coastal fogs. This fog drip can add over 20 inches of extra water to that which falls from the clouds.

Even the extra moisture from fog drip might not be enough to support California polypody were it not for this particular fern‘s ability to go into an extended period of dormancy. That is, the living green leaves simply die back to the under ground stem (rhizome) and decompose during the dry months. Therefore this fern actually totally disappears from view during the rainless months of the year.

This disappearance probably explains how it could be present, yet not recorded in a species list. Then when moisture returns to the soil, the buds on the rhizome produce one to several new leaves. A note about all of our native ferns, the only visible vegetative structures one can observe without digging are the leaves. Stems and roots are all below ground. California polypody appears quickly after the first rains of autumn.

Bonnie’s main drawing actually shows two non-seed producing plants. The larger one, as stated above, is the common or California polypody or Polypodium californicum. The smaller, but more numerous is some kind of moss. I have no idea what kind. Mosses and their closely related liverworts and hornworts are usually neglected in nature books.

Neither mosses nor ferns produce seeds. Seeds are complex multi-cellular reproductive structures that consist of at least three parts. These include the outer, protective seed coat whose cells contain DNA that is identical to the mother plant, a food supply (endosperm) often consisting of cells controlled by 2/3 mother and 1/3 father DNA, and an embryo whose DNA is one-half from each parent.

Seeds allow land plants to disperse over a land environment. Mosses and ferns do not produce seeds, yet they too are land plants. So by what devise do they disperse over land? They use spores.

Spores are simple, unicellular structures that are enclosed in a thick wall. Like seeds, spores usually are capable of a period of dormancy before they can germinate and grow. In the true plants (Kingdom Plantae, which includes mosses, ferns and seed plants) all spores contain a single set of chromosomes (haploid). In all true plants, spores are always produced in a capsule-like structure called a sporangium, each of whose cells contains two sets of chromosomes (diploid). Since the cells of the sporangium are diploid and the spores produced inside are haploid, something special must happen to at least some of the cells inside the sporangium. This special type of cell division occuring when a single diploid cell (spore mother cells) divides its chromosome number in half producing four haploid spores is meiosis. All sexual organisms do this process some time in their life cycle.

The stalked sporangia in common polypody are produced in clusters on the underside of leaves. These clusters are termed sori (plural) or sorus (singular). Bonnie has drawn a portion of the underside of a leaf lobe showing several sori. A typical, single, tiny, stalked fern open sporangium is also shown.

When these haploid spores germinate, they do not produce the fern plant one sees growing in nature. They produce a tiny, barely visible to the naked eye, haploid plant known as a gametophyte. This little plant, (not shown) produces the sex organs that produce either the sperm or the eggs. These gametophytes live on the soil surface where periodically there is moisture enough to create a film of water over soil and plants. The sperm then swims through this film of water to the egg. The fertilized egg grows into the typical visible fern plant that Bonnie has drawn.

Each cluster (sorus) contains a few score of sporangia. Let’s say 60 sporangia. Each sporangium produces approximately 60 spores so a single sorus would be expected to produce 60 x 60 = 3,600 spores. Each leave produces about 20 sori, so the number of spores produced per leaf would be 72,000. Each individual fern plant produces at least 10 leaves so the number of spores per plant is now 720,000. But the California polypody is a perennial and it produces spores almost every wet year of its life. If we are conservative and say a given fern individual encounters only five wet years during it life, then during that individual’s five-year life, it will produce 3,600,000 spores.

How many of these spores must be successful in order to produce a stable population of fern plants? The answer is only two! What happens to the individuals that could have been produced from the other 3,599,998 spores? They die. If 3 or more are successful, the ferns population increases, if only one or none then the fern population decreases.

by Dirk Walters, illustrations by Bonnie Walters | Dirk and Bonnie Walters are long-time CNPS-SLO members, contributors, and board/committee participants. In addition to his work at Cal Poly, Dirk is the current CNPS-SLO Historian.
Umbellularia californica

Umbellularia californica

California Bay Laurel

Bonnie’s cover drawing this time is a modified repeat from May 2009. It is derived from one that she did for David Keil and my plant taxonomy text. My guess is that it is a tree that almost all of you know already. It is one of the first trees for which I learned its name. It is known locally as the California bay laurel or simply California bay. Its scientific name is Umbellularia californica and belongs to the laurel, sassafras, cinnamon or camphor family (Lauraceae). As can be surmised from the drawing of a flowering twig tip, it produces small flowers. Each yellowish-green flower cluster turns into a single dry olive-like fruit.

Why discuss this species so soon?

It’s because Heather asked me to explain the new family placements in the new Jepson Manual. Up until the middle of the 20th century, the flowering plants were divided into only two taxonomic classes. These were the monocots and the dicots. Different taxonomists divided the flowering plants in various ways, but none seriously messed with the dicot/monocot distinction. Then in the late 1960’s, Arthur Cronquist came up with a new classification for the dicots which accounts for 2/3 of the flowering plants. It should be noted that he too didn’t mess seriously with the two classes – dicot and monocot. What he did do was recognize an evolutionary basal subclass he called the Magnoliidae.

This subclass contained many woody plants which displayed characteristics that he considered very primitive. These included such traits as a wood anatomy more like conifers than the rest of the flowering plants. A few of them, but none of our native California plants, even had immature seeds (ovules) that were exposed to the open via an opening in their ovaries which resulted in a pollination process where the pollen landed directly on the ovule. Again this is reminiscent of what occurs in gymnosperms. One thing we need to remember about the plants classified in this subclass is that they all produced true flowers so there was no controversy about their being flowering plants.

DNA Sequencing

We now skip ahead to the 1980s and 1990s. Genetic procedures were developed that allowed the molecule DNA (deoxyribonucleic acid) to be readily extracted from organisms and duplicated rapidly. This produced sufficient quantities to be easily studied. Studying DNA means determining the sequences of the four nucleotides that are found in all DNA molecules. These nucleotides include A (adenine), C (cytosine), G (guanine), and T (thymine). Basically all DNA molecules contain long sequences of these four nucleotides in patterns unique to the group to which an individual organism belongs. Each individual within a group also possesses DNA sequences that are a very slight variation of its group DNA.

At this time plant taxonomists combined the newer DNA sequences with older morphological (form or appearance) and biochemical traits (as well as fossil evidence where available) into extremely large data tables (similar to computer spreadsheets and tables produced in Microsoft WORD and EXCEL only larger and read by different software. These huge data sets required computers running specialized analysis programs. These programs basically create groups of species on the basis of similarity using all the characteristics including DNA sequence data. That is, it would first link species together that shared the most characteristics. Then it would combine these new groups, again based on combined similarity, into a smaller number of slightly larger groups.

If you repeat this procedure long enough, it will produce series of fewer but larger clusters. Ultimately, the large number of individual starting groups (species) will end up in a single, all encompassing group. The computer can also produce a picture of the process. This diagram resembles an intricately branched shrub or tree. In the diagram (right)california native plant society, species (or genera or families) are represented by letters and the numbers represent degree of similarity or percent of shared characters. In the diagram below, the many first-formed, highly similar small groups appear to the right of the tree or at the branch tips while the few last formed, diverse, composite groups appear toward the left. I’m guessing that some of you will picture the tree as potentially representing an evolutionary sequence, with the more primitive groups at the left and the derived (advanced) groups to the left.

How does all this impinge on the placement of California bay, as well as spicebush (Calycanthus) and yerba manza (Anemopsis), in Jepson? Well, when this process was repeated many times by many researchers, it turned out that these plants fell not only below and separate from the rest of the dicots and monocots but also between the dicots and monocots. The only way to translate these relationships into a classification system was to create a new category of flowering plants that is neither monocot nor dicot but equal to them in rank. This is the “magnoliids.”

Examine the Bay Laurel

Look at Bonnie’s picture of the enlarged flower. Count the sepals (it doesn’t have any petals). There are six, which is a monocot character. There are also nine stamens also on the monocot 3-merous plan. Note that the plant is a tree whose trunk increases in two diameter via a cylindrical layer of dividing cells (cambium). This, the pinnate veined leaves and two seed leaves (cotyledons) found in the embryo are dicot characters. So even without the esoteric DNA information, a case can be made for the creation of this NEW class of flowering plants to contain intermediates such as our California bay.

by Dirk Walters, illustrations by Bonnie Walters | Dirk and Bonnie Walters are long-time CNPS-SLO members, contributors, and board/committee participants. In addition to his work at Cal Poly, Dirk is the current CNPS-SLO Historian.