Re: Pistia in New World

From: Matyas Buzgo buzgo at systbot.unizh.ch> on 1999.12.10 at 15:14:15(3919) Dear Aroiders The question, when and how Pistia occurred first in the New World is unanswered, and may stay unanswered. Pistia seeds are up to 2mm long and 1mm in diameter. So, they are NOT transferred by wind. They are shed in a mucilaginous matrix, rather hidden by old leaves and roots beneath the main mass of the plant. Soon, the matrix decays and the seeds sink to the ground. The seeds stay at the ground until germination is induced. Therefrom, it is not very plausible that bird dispersal of the seeds is frequent, though it certainly occurs. However, main dispersal appears to be by young plantlets Pistia produces on stolones: The stolones break easily and the feather-shaped roots enhance the ability of the plantlet to attatch itself to animals or objects, similar to other aquatic plants (Salvinia, Phyllanthus, Azolla, Lemnaceae, many aquatics in germination stage). Thus: it is possible Pistia reached the New World without human help, obviousely quite some time ago, and may be considered native. At least, until the opposite is proved. wkr Matyas Buzgo +More buzgo@systbot.unizh ch

Note: this is a very old post, so no reply function is available.