paghat wrote:

In article , Pam wrote:

Iris Cohen wrote:

Both male & female plants must be present for the
long-lasting fruit to occur,

Are you sure? I thought in the Araceae both male & female flowers
occur on the
same spadix.

You are correct - aroids can carry perfect flowers on a hermaphrodite
infloresence
or separate male and female flowers in zones on a monoecious
inflorescence. At any
rate, both sexes are contained on the same spadix. Big ariseama
collector here -
all of mine produce copius berries.

pam - gardengal

A. triphyllum is not hermaphroditic in the sense you're stating. It may
produce male flowers one year, female another year, but is not
self-pollinating being one or the other at any given time. Since they can
change back & forth they're hermaphoriditic yes, but not in a given year
for this species.

Generalities: Young plants & stressed plants produce spathes containing
only male organs; older plants that have stored sufficient energy produce
female organs hence berries. This is not true of all species of
Jack-in-the-Pulpits (certainly not true of all aroids) but it is true of
this specific j-i-t-p. See Dr. Paulette Bierzychudek on A. triphyllum for
specifics of their biology.

The sex life of arisaemas is truly fascinating and typically complicated and I
was not aware that A. triphyllum (and a few other species, too) were able to
change their sex according to conditions. The native jack-in-the-pulpit is not
one that I grow, tending towards the more exotic Asian species. Thanks, it's
always good to know another interesting little horticultural tidbit.

pam - gardengal