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From: "Jim McClements, Dover, DE z6" <JimMcClem at AOL.COM>
Subject: Re: Arisaema flavum variability
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In a message dated 12/7/01 9:55:55 AM, Renner at UMSL.EDU writes:

<< Publications before 1990 also describe A. flavum as a non-sex-changer.
However, a sex-changing subspecies of A. flavum has been discovered
(Murata, 1990).  It is diploid and has relatively large spadices.  The
other two subspecies of A. flavum are tetraploid, have minute spadices (c.
1-1.5 cm long), and are the only arisaemas capable of selfing (Vogel &
Martens, 2000).
>>

Susanne

By a "non-sex changer" I assume that you mean that the adult plants are
monoecious, containing both male and female flowers. That has been the
conventional view of the species, as far as I know.

Does the"sex-changing" subspecies ever become monoecious, or is it always=one
sex, like most arisaemas? And does it have a name? Where does ssp. tibeti=cum
fit into this picture? Is it the diploid sex-changer?

With regard to the "selfing" question, isn't any monoecious species capab=le
of this, at least in theory? I can't swear to it, but i think I've seen A.
tortuosum, which is monoecious, self-pollinate. Theoretically, the male
flowers shed their pollen before the female stigmata are receptive, but s=ome
overlap can probably occur.

As far as I can remember, A. flavum and A. tortuosum are the only two spe=cies
that are normally bisexual. Do you know of any others? Some of the single=-sex
species seem to go through a year or two of having flowers of both sexes =on
the spadix while making the transition from male to female, A. candidissi=mum
being one of those. "Selfing" is also theoretically possible in that
situation, and may explain some of the reported incidents of apomixis in
arisaemas.

Jim McClements