Help on identification: Arisaema dracontium vs. Pinellia pedatisecta

[George R Stilwell, Jr.]

Bjoern,

I think the easiest way to distinguish A. dracontium from P. pedatisecta
is by size. A. dracontium
is much, much taller (up to a meter), P. pedatisecta is rarely over 10 to
12 cm tall.
The leaf on A. dracontium is solitary with 7 to 19 segments in a rachis
(sp.) form like the antlers
of an elk.

If you look at the picture of it growing beside the house on Roy's page
<http://genesis.ne.mediaone.net/~rrh/Pages/ardrac.html> you'll get an
idea
of the magnitude of the plant by comparing it to the shake shingles on
the house.

For a look at Pinellia pedatisecta, see
<http://genesis.ne.mediaone.net/~rrh/Pages/pinellia.html>
also on Roy's page. Note the dainty inflorescence compared to the larger
and more robust
Arisaema.

A. dracontium berries are indeed red when ripe and they do contain
multiple seeds
(5 is the most I've counted). The seeds are usually quite a bit larger
than those of
A. candidissimum, but this may depend on culture. I'd be surprised if
they were ever
much smaller.

Roy also points out on the page that:
1.Pinellias never have more than one seed per fruit.
2.The Pinellia seedhead flops down on the ground to disperse the
seeds, which are still green when ripe.
3.The Pinellia flowering stem has no leaves. The leaves arise directly
from the tuber.
4.The Pinellia spadix is fused to the back of the spathe for some
distance.
5.Pinellias bloom several times in each growing season.
6.All Pinellias are monoecious (ie, male and female flowers on the
same inflorescence)

A. dracontium is quite different on items 1, 2, 3, 4, 5, and 6.

<GRSJr at Juno.com>

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