What is a bulb?

AW awilson@avonia.com
Mon, 07 May 2012 17:44:07 PDT
Dear Nhu Nguyen,

I was totally surprised by your most recent posting. It seemed to be in flat
contradiction with the key in 'What is a Bulb', inserted to define what was
acceptable to PBS as a bulb. I thought that was meant to provide the
defining word here. Question 2 of the key says: "2. Is the plant generally
recognized to grow from some sort of thickened storage organ (a bulb, tuber,
corm, thickened rhizome, thickened root, or fleshy pseudobulb)? In other
words, would scientists call it a geophyte? If the answer is yes, we include
it. If no, go to question 3".

Thus, the presence of a thickened storage organ is a criterion for
acceptance, which means that orchids possessing fleshy pseudobulbs are
accepted. If you have subsquently decided not to include them you had better
correct the key.

I wrote a message here yesterday showing an orchid with a massive set of
fleshy pseudobulbs. It would certainly be far closer to what we think of as
a clump of bulbs than so many other genera considered here. Indeed the
pseudo bulbs do look comparable to your example of 'Crinum and Ismene'.
Living atop granite outcrops the orchid cited uses its massive pseudobulb
system to store water during the long, cool dry season. If the preference of
PBS to eliminate such plants, so be it, but you then really do need to
reformulate 'what is a bulb'. 

San Diego 

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