(Johannes Ammann was an 18th Century botanist. Latiflolia means wide leaves.)
John and I worked at Haney Creek Natural Area near Jensen Beach, Florida, this week. Much to my delight as a lover of things in wet places, we saw an old wetland oddball plantfrind, always under-appreciated. The sort of plant you step on looking for something “interesting.” It is all interesting if you look closely, or if you read research by other people, especially other people with an electron microscope. Today I’m paraphrasing an eye-opening paper by Dr. Shirley Graham (in the Journal of the Arnold Arboretum, vol. 66). Because the work dates to 1985, I’m confident Dr. Graham and the Journal would have no objection to reappearance in a 2019 blog, and I sent her an e-mail to make certain.
Today I was doing what I like to do, walking along the dried out shore of a nearby stream-canal where only two living things were visible on the barren mud, one a green alga, the other, as at Haney Creek previously, scattered individuals of Ammannia latifolia livin’ the vida sola. Just desolate mud, a little algae, and big red Ammannias.
Life “on mars” takes a fairly special plant. Ammannia has some obvious advantages for places that alternate between flooding and drought, with suffocating soil. It is a wee bit succulent, has rugged leaves, has red coloration which may be sunscreen, and has padded little pea-sized capsular toothcup fruits. The flowers may or may not have petals, that’s odd, and it can sometimes, or perhaps predominantly, set seeds without benefit of outside pollination, a handy trait in a lonely pioneer. The pollen-making anthers can break off and adhere to the pollen-receptive stigmas in the same flower assuring self-pollination emphatically. The roots tolerate saturated mud.
That is all well and good, although perhaps unthrilling. The magic is in the seeds, as Dr. Graham related. The electron microscope photos below are from her 1985 publication.
The seeds are packed a couple hundred per fruit. They float, and have a special mechanism to do it well: On one side of the seed there appears a small puffed up beer belly, a flotation device, which collapses when the seed dries.
Even weirder, there are hairs on the inside of the seed coat, wrongside-in. When the coat is moistened the hairs pop outward to become spikes like the antennae on Sputnik, where they may help water enter the seed.
The moistened seeds become a little sticky, which may help them grab hold to a final sprouting site, or may help them cling to a bird’s leg en route to the next aquatic environment. The seeds are willing to germinate in a few days under favorable circumstances, and if things aren’t optimal some are patient and tough, reportedly germinating from dried museum specimens 27 years old.