A. triphyllum

[George R. Stilwell, Jr.]

Member George Schmid has posted this on Aroid-L. For those not on that
list, I repeat it here.

Ray

Currently, there are 3 subspecies, aside from the typical plant: quinatum,
stewartsonii, and pusillum. I am currently writing a paper for Aroideana on
sorting this out. Unfortunately, UGA herbarium, which has the holotype of A.
quinatum was closed for construction earlier this year and I am now playing
catch-up.A. quinatum has been misunderstood by previous researchers, who
apparently did little field work in the southern part of the eastern U.S..
They worked with herbarium specimens and did not get the true picture of
what grows out in our woods. I have corresponded with Guy Gusman. Since the
publication of his book, he has received plants of A. quinatum and he now
states that he considers this a separate species, as do I. It flowers 2-3
weeks later, and has a unique inflorescence, aside from five leaflets on the
primary leaf, each with its own stem (petiole). The typical form does
occasionally develop 5 leaflets and that has side-tracked other researchers.
Two pairs of these leaflets grow from the same leaf stem, i.e., they do not
have separate petioles. A. pusillum is also a later-bloomer, later than A.
quinatum and has small flowers. Right now the standard type is forming seed
pods here, A. quinatum is in full "bloom" and A. pusillum is just opening
up. I have observed and photographed A. quinatum and A. pusillum.in several
southern states GA, AL, NC, SC, TN, northern FL. FL and TN herbaria have
specimens of A. quinatum. A. stewartsonii is regarded by many as a separate
species with prominent, white ridges in the hood structure. It does however
bloom at the same time as the type, so there are questions. The type itself
has an incredible number of variations in the inflorescence coloration from
all white to very dark (almost black or dark maroon, purple. The leaflets
can be green, green with variegated striping, maroon shading, all over,
maroon veining, and the formation of lobed structures ("leaflets") on the
two outer leaflets, so appearing to have 5 leaflets. They do however have no
petioles and are part of the outer leaflets or, if they have five distinct
leaflets, they emanate from a branched, outer petiole. Sizes also vary quite
a bit. The largest I have photographed I found right here in Tucker, GA, and
they extend to 120 cm (48 in). The pseudostem at ground level measured 2
inches in diameter. I have a picture of that giant in my book. As to
habitat, I have observed most of the southern species in acid pine and oak
forests, not necessarily wet shade. They are usually near or mixed in with
Trillium, Medeola, Streptopus, Polygonatum, Orchis, Cyps (sometimes in pine
forests). This group of NA arisaemas is extremely adaptable. Yesterday I
visited an area in Tucker, GA (private land now) with indigenous populations
samples of A. quinatum and found that near water they grow taller but that
may also be caused by better soil. They grow in dry as well as wet shade and
in some cases in swampy conditions, but that seems to be more the case in
the northern states. There are about two dozen synonyms, which encompass all
three species. A dark-striped inflorescence has given rise to "atrorubens"
and I see nothing wrong in considering this a selection of the type and to
give it the cultivar name (under the ICNCP) 'Atrorubens'. There are many
other variations that have been named. I suggest you peruse the archives of
the IAS (International Aroid Society) at aroid.org. HTH, George

W. George Schmid
Hosta Hill - Tucker Georgia USA