John and George took to the scrub today in Seabranch State Park near Hobe Sound, Florida. Sunny but nippy The recent rains have made the lichens soft, the spiders hide, and scrub plants grow new “spring” basal growth. The only two species showy-flowery today were American Nailwort and Bluecurls. Both are pretty little curiosities. The Bluecurls is showier, so it gets to glory.
Handbooks generally describe Forked Bluecurls as annual, and no doubt it is often, but possibly not the whole story. Today new growth was rising around the bases of last year’s stems, growing from deep taproots, making the plants at least in today’s experience what I’d call scrub perennials, several species there behaving identically. Forked Bluecurls seems remarkably lightly studied, given its good looks. Most Trichostema species live in the arid West, and have received more attention there. So now hear this: today is interpretative and based on the botany of other Trichostema species. This is my speculative extrapolated “take,” not established fact.
Beyond the coloration, the outstanding attribute is a set of long curled (pollen-making) stamens and one longer (pollen-receiving) style reaching out the front door of the flower. The outreach may seem an obvious adaptation to dust pollen on the back of a bee, but there’s more to think about. First of all, why the bee’s back? The bee does not have a back-scratcher, and can’t remove the pollen burden.
And why the long down-curled configuration? Here is how an observer in the 19th Century described the similar flowers in California Trichostemas:
See the bee CLICK (on similar California Trichostema)
Early when the flower is open, the stigma (pollen-receiving organ) sticks out just a little more than the stamens. Makes sense—pick up incoming pollen from the arriving bee before depositing new grains on it. True of many flowers. Okay then.
But as the flower ages, the stamens and style continue curling inward into a position where bee-pollination can’t happen. Self-pollination has been reported in our local species and in other Trichostemas. I think, and this parallels many other plants, the severe incurling represents a back-up mechanism, plan B, self-pollination after giving the bees first dibs.
Trichostema is an appealing mint, complete with a pleasing minty fragrance to the fuzzy-sticky leaves. Some mints share a trick with likewise strongly bilateral orchids…twisting their flowers 180 degrees, called resupination. The Bluecurls flower looks like an orchid (or vice versa if you are not an orchid chauvinist). Trichostema twists in an unusual way with apparent unusual “purpose.”
The calyx (small green cup around the base of the flower) has five triangular lobes on its rim: three together and long, and two together and short. (In most mints the three long are on the floor side of the horizontal calyx and the two shorter ones at the roof side.)
When the blossom is at its early peak for pollination it stands nearly vertical. The three long calyx lobes stand behind the blossom as the bee approaches, forcing the blossom and the curling sex organs to bend forward onto the bee as it rests on the dotted landing-lip. Those three tall lobes, like fingers behind a basketball in a freethrow force the action forward.
Then their role and position changes. After pollination, the blue petals drop away leaving the calyx containing four “seeds” (nutlets). To keep these from falling out prematurely, and to give them a springboard (almost literally) at the right time, perhaps when a raindrop strikes, the cupular calyx twists 180 degrees relocating the three long calyx lobes to the doormat position and the two short lobes as an awning over the door. The seeds roll out onto the 3-lobed diving board.