Thursday, March 31, 2011

Wickham Park: Ladiestresses, March 31, 2011

Yesterday I happened to notice two ladies'-tresses (or ladiestresses, as the USF/ISB online plant atlas calls them) growing near the volleyball courts. I didn't have my camera with me that day, so I returned around noon today ready to photograph them. It started raining just as I approached the flowers; then came close flashes of lightning. Standing under tall pine trees in a thunderstorm is not good, so I quickly fired off a few shots, some of them with flash since storm clouds had darkened the sky, and headed to my car for safety.

The primary characteristic of ladiestresses is the flowers usually form a spiral around the stalk, hence one of their common names, spiral orchid; the genus name is Spiranthes. According to the USF/ISB online plant atlas, there are 22 species of Spiranthes in Florida, all of them native. Five of the 22 species have been found in Brevard Co. They are: S. laciniata, S. odorata, S. praecox, S. sylvatica, and S. vernalis. Of those, only S. praecox (greenvein ladiestresses) and S. vernalis (spring ladiestresses) are described by Wunderlin as common. Others were characterized as frequent, occasional, or rare. Both S. praecox and S. vernalis are found in similar habitats: wet flatwoods, marshes, and open, wet, disturbed areas. The area where I found the two plants was definitely wet flatwoods--the ground was squishy (it had been raining for the past several days) and the plants were in pine flatwoods.

There were two clumps of the plant, about 1 ft. apart; one with two flowering stalks and one with four flowering stalks. Basal leaves were grass-like.

One online source stated that S. vernalis is distinguished from others in this genus by the "presence in inflorescences of copious articulate, pointed trichomes." Another online source states that in S. vernalis sepals and petals clasp in a hood over the lip, which "often shows a pair of brown dots when it ages." The plants I found appear to have some fuzziness (i.e., trichomes) on the flowers and the lips show a pair of brown dots. Although my skimpy evidence points to S. vernalis, I didn't examine the plants closely enough to confidently identify the species.


  Ladiestresses (Spiranthes spp., Orchidaceae)

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