A. triphyllum variants in the woods

Mike Slater mslater at VOICENET.COM
Fri May 16 04:27:18 CEST 1997

Hello to all Arisaema enthusiasts,

I have been walking in the woods over the last two or three weeks
observing the spring wildflowers in bloom including many, many Arisaema
triphyllum, one of the commonest ones around here. The variation in the
flower color and size have always been amazing and bewildering to me,
but this year I have been observing the variations in color of the
spathe and spadix as well as the varying length of the overhanging tip
of the spathe in more detail. The combinations I list below are what I
have found so far here in Southeastern Pennsylvania (Berks & Lancaster
Counties) and they seem to be almost randomly distributed in the woods
except for one unusual form I will elaborate on later.

Note: Please see my note below about the names of species that
supossedly exist around here according to botanists at one time or

All of the A. triphyllums I have observed have been green on the outside
of the spathe, but the inside is another matter!

Color types - There are gradations between all of the color types

Color type 1) (GG)      Inside of the top of spathe (the tongue like
appendage on top) is green and the spadix is green also.

Color type 2) (GP)      Inside of the top of spathe is green and the spadix
is purplish black also. Sometimes there are very nice vertical stripes
displayed on the back of the spathe.

Color type 3 (PP)       Both the inside of the top of spathe and the spadix
are purplish black. The chalice-like part of the spathe always is
greenish on the inside where it wraps around the base of the spadix.

Color type 4) (Theoretical I haven't found one yet, maybe it doesn't
exist because of the order of pigmentation in the developing plants.)
(PG) Purple spadix and green spathe.

And then there is the physical form of the flowers. All but he third one
seem to exist in any of the above color forms.

Form Type 1)    (short tongued form) Spathe tip hanging down less than
halfway to the bottom of the inflorescence. A little bit of pulling is
done to see the limit.

Form type two)  (long tongued form) Spathe tip hanging all the way to
the bottom of the inflorescence.

Form type three) (upright tongued form) Spathe tip semi-erect, held at
about 45 degrees, so the spadix can be easily seen when the flower is
viewed directly from the front. **This is the one that seems to come in
only one color form and size, (PP) Dark spathe and dark spadix and
relatively small flowered (only 2 inches or so)!** It is not randomly
distributed in all woodlands but is restricted (in my small sampling
this Spring) to two small populations in Berks County, It grows only in
areas of seeps and springs with very wet soil covered with mosses and
also with plants like Marsh Blue Violet, Viola cuculata, and Golden
Saxifrage (or Water Carpet), Chrysosplenium americanum. Has anyone else
seen ones like this?

The size of the flowers and plants varies greatly with age, health and
sex of the plant from 5 or six inches up to 2 feet. This must be very
fertile ground for lumpers and splitters! Have botanist come up with any
good ideas or hypotheses? Have the all just thrown up their hands in
despair?  I guess that the little pollinating flies just don't care that
much but it makes my lunchtime walks more interesting.

I will happily correlate and tabulate any observations and information
from other places if people want to send them to me. Also any
information on the biology, ecology and chemistry of this variation
would be interesting.

A few other questions have come to mind:
Do these colors and forms stay constant in one plant from year to year?

What forms are dominant and which ones are recessive? (Assuming they
do interbreed, because they are usually only a few feet apart.)

I haven't done any counting yet to establish statistics on my walks
around here, but are the relative number of each variant constant over
the species range?

Please let me know what you have noticed in the wild and in cultivation.

NOTE: I have deliberately NOT consulted books or experts for
descriptions of A. triphyllum, A. atrorubens and A. stewardsonii, the
latter two being possible or probable synonyms for various form of A.
triphyllum, first I wanted to just observe for myself. Maybe I have even
seen the mysterious A. pusillum. I just started to look at the books and
I see in the Atlas of Pennsylvania Flora (Wherry, Fogg, & Wahl, U. of
Penn. 1979) that there is a Arisaema pusillum shown to exist in
southeastern Pennsylvania and that Arisaema list by Stilwell, Gusman and
and Walton lists it as a valid species too, but I don't have any
description of it. Help!

Mike Slater

|                              \   Mike Slater, DVC of NARGS
|                              /   Southeastern Pennsylvania, z6
|                           *  \   min temp -10 F (-23C)
|_______________/  http://www.voicenet.com/~mslater

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