Warm/cold dormancies

[Ellen Hornig]

On Sun, 21 Sep 1997, McClements, Jim wrote:

> Ellen
>
> The behavior of your A. triphyllums is sort of the converse of the way A.
> sikokianum and others have behaved when they start sprouting while still
> refrigerated. It's as if they have a "dormancy time clock" which overrides
> temperature considerations. I think I'll try a pot of sikokianum seedlings
> and see if they'll break dormancy in several months without a cold period.
> How dry did your triphyllum tubers get while being neglected? And did they
> start growing again as a result of increased moisture?

I can report that last year I had some sikokianums which failed to get a
cold dormancy, and they never did reappear.  Haven't checked yet to see
whether the tubers still survive.

I don't know how dry the triphyllums got - they may well have gotten quite
dry, but with several hoophouses to attend to, I more often than not fail
to pay close attention to the less demanding pots!  Conversely, they may
have stayed quite wet.  Who knows.  So much for science.  This regrowing
behavior is quite pronounced in the (probable) consanguineums I have; by
late summer both this year and last, seedlings that were started in winter
and dormant by early summer have sent up new, true, leaves.  Last year
these late growers were very reluctant to go dormant, too; they endured
cold fall weather and a transfer to the basement with great equanimity,
and didn't go dormant until mid-winter (and with some encouragement in the
form of my withholding water).  Then, despite careful chilling, they
refused to resume growth until well into summer.  I definitely think there
are some "timing" mechanisms at work there - now I wonder how to nudge
them back to a more reasonable schedule.

A couple of other observations while I'm here:

(a) I've done remarkably badly with many of the tubers I've grown from
seed and nurtured for several years: their numbers decline annually, and
this year amazing numbers bit the dust.  I think pot/ refrigerator
culture, over time, wears them down.  Interestingly, this is not a
problem, as far as I can tell, with the species I'm producing from offsets
from mature stock. I wonder whether I'm letting the tuberettes get too
dry?


(b) in unpotting several A. triphyllum ssp. stewardsonii and "regular" A.
triphyllums, I was struck by how *very* different the tubers are.
The shape, positioning, and numbers of offsets (many) in stewardsonii
contrasts sharply with I see in other triphyllums.  I am also happy to
report that the stewardsoniis I collected in my back woods, and the ones
Roy Herold sent me a few years ago, have very similar tubers - guess I see
that as indicating that the distinguishing features are real, not random,
and exist in both Massachusetts and upstate NY (roughly 300 miles apart).
I'd certainly wonder whether they're the same species.

NB: Ray, I haven't forgotten!  Very soon....

Ellen