Plant of the day is: Polygala lewtonii or Lewton's milkwort
One of the things I love most about my job is working around such passionate people that introduce me to some of the best things the world has to offer. This little plant has an interesting and at times, sad, tale. Notice the flower structure below, it's quite unique.
Taxonomy, etc.: Unique enough to warrant a family. A member of the Polygalaceae family, or milkwort family. I don't believe I've covered this family before, kinda neat. The Plant List notes 27 genera for the family with around 1200 accepted species. Polygala is the type genus for the family. The genus has a near-cosmopolitan distribution. The inflorescence is a raceme of several flowers. Flowers have two large petal-like sepals (plural calyx btw.) on the sides. You can those sepals in the picture above. There are three smaller sepals found behind. The three true petals are joined at the bases the lower of the three making up the "keel" petal which is cucullate (hood-like). You can also make out above, the stamen and style that are found in the curve of the keel petal. All in all, a really interesting flower, and flowers are of course what taxonomic designation is all about. I can see why these get their own shout-out.
Description: A short-lived perennial (5-10 years) with a taproot. Fleshy stems arise from the taproot about 20cm tall. Leaves are alternate and overlapping. Leavers are linear to spatula-shaped and only about a centimeter long. THIS is the neat part here. There are three types of flowers that occur on the plant. What? Three types of flowers? That's crazy! The flowers on top are your typical chasmogamous flowers. You know, chasmogamous, "open marriage"? These are normal flowers relying on open pollination. This plant ALSO produces cleistogamous "closed marriage" flowers at the base of the plant. This is where it gets fun. These flowers, in the lower leaf axils, do not open and are self-pollinated. The THIRD type (what?!?!) is also cleistogamous and occurs underground and also self-pollinate. The very cool practice of developing seeds asexually is called apomixis. The even coooooler practice of producing above ground chasmogamous flowers and below ground cleistogamous flowers is called amphicarpy. Seriously folks, plants are SO much more than meets the eye. This is one of only a few DOZEN amphicarpic angiosperms known WORLDWIDE. Kind of a big deal yo.
But why!?: Seems like an awful lot of work huh? All those weird flowers, well, rest assured, there IS a reason. Firstly, I'll say that cleistogamous flowers are actually cheaper in terms of energy investment to make. They typically aren't fully formed complete flowers, they don't exist to attract pollinators so why spend the time and energy into nectar, color, petals, and the like? These plants still get the added benefit of sexual reproduction for genetic vigor (and better evolution) but the germination rates of the insect pollinated flowers are notoriously low (as low as 10%). This presents a problem for species conservation, that I'll touch on shortly. But why UNDERGROUND flowers and seeds? That takes us to our next topic...
Habitat: So I may as well mention now, this is endemic to Florida and a federally listed endangered species of the United States (as of 1993). :(. It occurs in the central ridge of the peninsula (the sandhills) and there are only about 49 occurrences of the plant remaining, most of which contain very few plants. The cause: Humans, habitat degradation, same ole story. It is a rather neat ecological area for plant life and there are several other plants that are endangered found in this habitat. In the instance of this plants demise, it's all about fire. Coming back to those underground seeds, they formed in case the plant up top gets roasted by a fire! Clever right? Dang clever. Smoke is thought to aid germination as well (I SO want to do germination studies on this plant). Fire helps eliminate competing plants and rejuvenates populations of the plant. The plant declines the longer its habitat goes without a fire. Absolutely atrocious fire suppression policies (country-wide really) coupled with the conversion of its habitat to citrus groves and residential areas has greatly reduced this species numbers and resulted in habitat fragmentation. Add to ALL of this the fact that some of the remaining populations are in areas popular for off-roading ....and you've just got all kinds of human neglect and failure.
The good news is that some populations are now on protected land with prescribed burns. Also, the passionate plant people of the world will be working to introduce new populations, bank seeds for long term storage, and test germination and development.
There is still some good left in the world Mr. Frodo. For a detailed report on the species as well as current conservation plans, the USFWS 5-Year Review is a great read.
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