What is a bulb?

Hannon othonna@gmail.com
Sun, 06 May 2012 21:46:06 PDT
Max asks 'What is the harm in loosely defining "geophyte"?'

PBS is a group explicitly dedicated to a particular group that can be
reasonably defined and kept within generally predictive bounds. Those
bounds serve all visitors to the site and are one of the cornerstones of
the Society.

The problems in definition here are similar to those encountered in
succulent plant societies, where debates emerge as to exactly what is a
succulent. Over many decades, a convention has obtained among the latter so
that various genera and families are regarded as belonging to the province
of succulents, with or without scientific definition. As with bulbs, some
honorary members are included because they fit a certain cultural approach,
even if actual succulence may be dubious.

A good example of pushing the definition (of a succulent), which is also a
good example of a crossover to bulbs, is the category of caudiciforms.
Often these are *geophytes* with orthodox annual shoots above ground-- the
only succulent part of the plant is its rootstock. I have seen very few of
these on PBS, e.g., Raphionacme, Monadenium, Talinum, Othonna, Tylecodon,
Euphorbia, and many others.

I don't know why it is the case that there should be a random sampling of a
few orchid genera on the wiki and a few aroids (groups with their own
dedicated fan clubs) while these decidedly geophytic succulent genera have
been omitted, but it would be good to ad some of the latter to balance the
necessarily heavy weight of the petaloid monocots. Inclusiveness is a
perfectly good thing when properly considered.

Can a definition not be too loose? "Bulbs" as used on the wiki is perhaps
primarily a horticultural category. Therefore the boundaries of geophytism
will be less strict than in other cases. But plants without proportionately
"fat" rootstocks and/or deciduous foliage, such as the grass trees and
kangaroo paws and Doryanthes, are simply not geophytes or "bulbs" by any
stretch of the imagination. Such errors should be corrected.

Instead of asking "What is the harm", better to ask "What is the good?"


On 6 May 2012 20:50, Max Withers <maxwithers@gmail.com> wrote:

> Jim,
> Apparently we have the Danes to thank for the various systems of -phytes:
> http://en.wikipedia.org/wiki/Plant_life-form/
> OED's first citation is 1896, an article citing F. W. C. Areschoug.
> It is interesting in light of the present discussion that geophytes
> originally fell under "cryptophytes", which would cover most of the
> not really geophytic taxa that seem to be causing such consternation.
> Perhaps we should change the name to Pacific Cryptophyte Society!
> I would only say to Alberto and Dylan and their numerous confreres
> that you are of course correct -- but what is the harm? More
> information, even if it isn't strictly on topic, is better, isn't it?
> I just cannot imagine anything bad happening because the wiki
> convinced some poor ingenue that Xanthorrhoea is a bulb. Admittedly, I
> have a casual interest in terrestrial orchids, but if they offended me
> I would simply refrain from visiting the pages about them.
> Best,
> Max Withers
> Oakland CA

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