Problem of corms and other propagating parts was corms formed from stolons

J. Agoston
Thu, 09 Jul 2009 13:18:49 PDT

You are right. Gloriosa, Sandersonia, Littonia, Colchicum are all corms.
Becouse they bear their eyes/buds on their surface, they don't have a node
(it is a thickened internode), they don't have any scales (only 1), they
don't have a basal plate, and they can store food for only 1 season, they
regrow yearly from the bud. Shape doesn't matter! Smaller ones bear 1 bud,
bigger ones 2, large ones 3-5 buds. Colchicum boissieri, Co. psaridis, have
corms like Gloriosa, they grow horizontally. I made a presentation in 2005
on the Horticultural University in Budapest about the various kinds of
propagating parts of the ornamental plants - sensu lato bulbs. But didn't
have the time to translate it....

Moreover orchids have pseudobulbs, but the naming is misleading, they should
be called pseudo-corms becouse the only difference between them and the
corms are that they grow OVER ground. Like Pleione. Cypripedium is a bit
difficult, the pseudo-corms/bulbs live more than 1 year, they have buds on
their surface and some of them lay dormant, but the longitudinal section
shows no scales...

By the way Crocosmia is the typical example of forming corms on stolons.
Gladiolus also does but on short (0,1-2 cm long) stolons. But allways the
last internod thickens. This is a quite big problem, using the correct name
for each propagating part. Some plants have even more confusing parts, like
Alstroemeria, it is rhizomatous, but the rhizome's "job" is to bear the buds
and roots, and make the plant spread. The roots are thickening they store
food and water.

I have managed to get the Bulbs book of John E. Bryan, which is a very good
book, a lexicon of bulbs. But sometimes I think there are confusions
regarding the correct usage of names of propagating parts. For me it is
srtange to read "rootstock" we use this word in dendrology and fruit trees
(=rootstock+scion). This can be becouse I'm not a native speaker of
english... But the book is all right and invaluable for every geophyte-fan!

The other problem is that I was not able to find a correct definition for
bulb, corm, rhizome, tuber, ... This causes even more confusionI think! So
we started to make... But we didn't have had enough time to correct them, we
just agreed that for example rhizome and stolon are almost the same, the
only differens is their internode/diameter ratio, if internode length is
smaller than the diameter it is a rhizome, if longer it is a stolon.

Z5a, Hungary

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