Sunday, July 13, 2014

Rain lilies and botanical terminology

Cooperia drummondii, evening rain lily

I learned a new word last week. I was reading a study on watermelon pollination where an author had tracked the timing of a potential pollinator's floral visits versus the receptivity of the plant. Watermelons have male and female flowers and are entirely dependent upon insects for pollination. Their flowers are only open for part of one day-- early morning to early afternoon. On top of all this, visits to male flowers are only effective for pollen collection after anther dehiscence; that is, after the anther splits along its seam and releases pollen grains. If ever a plant had all its eggs in one basket, the watermelon is it. No un-assisted selfing or wind pollination for this species.

Rain lilies open along three seams to release their seeds
Dehiscence doesn't only refer to anthers. It is the proper botanical term for any 'intentional' release of material upon the splitting of a seam.  In the picture at left, you can see a rain lily  beginning to dehisce and release its seeds.

I've mentioned rain lilies in this blog before, and they may be my favorite wildflower I see around my neighborhood. I like the way they pop through lawns like mushrooms after a heavy rain. Their  expedited growth seems to allow them to persist in mown areas. They flower so quickly that if someone skips mowing for a week they can bloom and set seed.

We got good rains this spring/early summer in Fort Worth, so it seems to be a good year for rain lilies.    I'm collecting as many seeds as I can. I'm going to scatter them in my lawn, especially in any areas where the grass is thin. Goodness knows I'm negligent enough with my yard work that they should thrive. 

Evening rain lily (Cooperia drummondii) is more common in this area than the hill country rain lily (Cooperia pedunculata), but I've found both. C. pedunculata has bigger flowers and a 'peduncle', a distinguished flower stem attached to the main stem. The hill country rain lilies I've seen may be someone's garden escapees. 

C. pedunculata on the left, C. drummondii on the right.
Peduncle circled in red.
Cooperia drummondii seed heads in situ
Most of the seed heads aren't quite ripe yet. Ideally the seed head will be dried like paper before you harvest. My problem is that the seed heads tend to split (i.e., dehisce) almost immediately upon ripeness. I'm not quick enough to pick them. I'm experimenting with picking some a little early to see if the seeds are viable.  I tested the seeds, and they are black and doughy. I'm hopeful. Another tactic to try is bagging the seed heads prior to dehiscence. Seed collectors sometimes do this for milkweeds. When the seed head splits, instead of being scattered in the wind, the seeds are captured in a collection bag.
Another thing to consider: many ephemeral species do best when seeded immediately after flowering (unlike the majority of perennial seeds which favor dormant season seeding). I'm going to toss some seeds out now and sow others in late fall. I'll have to remember where I did what so I can learn which works best for these lilies! 

1 comment:

  1. I've had some grown from seed in small pots since 2006 and they still haven't bloomed. they don't get much attention, and i am about to move them to a permanent location in the ground. They main thing is--they sprouted relatively easily.