Re: Sensitive Plants

Michael (IFMJC@asuvm.inre.asu.edu)
Tue, 27 Jul 1993 09:01:58 -0700 (MST)

Ok, as ex-cactus Horticulturist at the Desert Botanical Garden, I sould
say that yes, the filaments of _Opuntia_ flowers ARE thigmatrophic. It is
best observed on some of the large-flowered prickly pears. I don't recall
whether chollas show any thigmatropism, but I would not be surprised if
they didn't. Other than the prickly pears, I can not recall ever seeing
thigmatrophic stamens in any other cactus. Of course, there are umpteen
other plant genera that do show this behavior (best is the trigger orchid
which shoots its pollinia! Ok, I know that's different. And what about
the trigger plants _Stylodium_ (sp?) anyone ever buy some of these from
Allen Lowrie?

In Connecticut I also found a wild legume which looked much like the sensitive
plant. It would fold up its leaves if given a stiff whack! There are other
plants families with pulvini. One that comes to mind is the prayer plant
family Marantaceae. These fold up their leaves at night into a "praying
position". (This is a really neat family with many highly ornamental species).
-Michael