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.