Dichelostemma--Themidaceae?
Antennaria@aol.com (Tue, 27 May 2003 20:29:30 PDT)

Comments on several respondents offerings on this topic:

Thanks Alan,
I shall give these a lookup sometime. Until such time that I get a chance,
can you summarize, is Muilla now in the Themidaceae? If it is, it's ironic
n'est pa?

Mar Sue, thanks for the paragraph summarizing the differences between
Alliaceae and Themidaceae. Some comments:

This is a gross generalization. Many alliums do not have a recognizeable
bulb whatsoever
. many Chinese species, such as A. wallichii, have nothing more that a
ever-so-slightly thickened leaf base, and some fleshy white roots, nothing that
you'd remotely call a bulb, but indeed merely a rhizome, and even questionably at
that. A large number of species do not have membranous bulb coats... some
do, some have fibrous bulbs coats, some have no recognizeable bulb coats
whatsoever.

I do agree that Trits and Brodes have corms, but some Geranium species, as
well as some Pelergoniums, have bulbs or bulb-like storage structures whereas
most are fibrous rooted perennials. Are they removed into their own genus?
Alliums can have true bulbs, rhizomes (whole sections named after this feature),
or a combination of vestigial bulb and rhizome. Should the different groups
be separated into their own genera? Many genera exhibit similar rootstalk
diversity, such as Corydalis... should these be separated out into their own
family?

Some major sections of the genus Allium also lack the characteristic onion
odor. Should these non-alliaceous-scented alliums be split off into their own
genus, or a new family perhaps.

Alliums have *one* to *many* bracts that enclose the flower buds, not always
a pair as described above. The number of spathe or bract segments, and
whether the segments are persistent or not, play a role in species determination.
In some species the spathe is so short and ephemeral (dropping off) that the
buds can appear as not being enclosed. The genus Muilla is described as having
buds enclosed in several spathe segments. What am I missing?

Alan writes:

Way back when, many S. American plants now known as Tristagma, Ipheion,
Nothoscordum, and others, were listed as Brodiaeas, even a few as Allium. Alan is
quite right, there are no true Brodiaea in Chile and these genera names were
misapplied. When it is said "all Chilean onions are still onions", I assume
what is meant by that is that all Chilean Alliaceae are still Alliaceae, because
there are no true onions (Alliums) in South America.

But this Themidaceae separation has me wondering... was the division largely
devised based on Western American and Mexican taxa... if so, therein lies the
conventional flaw in not looking "big picture". Most American Allium fall
into a single type with bulbs. Consider the genus Allium in it's holistic sense,
including Chinese Allium, the "rhiziridium" section of Allium, the
stoloniferous Alliums, alliums with varying bract structure, rootstalk structure, even
onion smell, and tell me that Themidaceae is justified. I just want to be
convinced. I'm not adverse to sensible change, but this one really has me
wondering.

Mark McDonough Pepperell, Massachusetts, United States
antennaria@aol.com "New England" USDA Zone 5
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alliums, bulbs, penstemons, hardy hibiscus, western
american alpines, iris, plants of all types!