The challenge of Utricularia

[John Grehan]

>A student here is doing a term paper on bladderworts and asks if there has
>been been published a phylogeny of the genus recently, of if anybody is
>working on one. Considering the fascinating specialisations seen in
>Utricularia, its wide distribution  and the general interest in carnivorous
>plants is quite amazing if nobody has looked into it since Taylor's
>monograph from 1989.
>
>------------------
>Finn N Rasmussen

If the student is interested in the fascinating specialisations one might
consider reading Croizat's 1961) discussion of their morphology and evolution.
Sometimes the most insightful investigatins don't necessarily come from
the most recent literature. Croizat's study is not a formal phylogenetic
account, but if the issue or interest is in their specializations then
Croizat's
account is a must, particularly as it challenges traditional models of
botanica
structure. For the hapless student, and those interested, I excerpt below
some comments by Heads (1984) on the matter:

"Notorious among traditionally minded botanists are carnvirous plants such as
Utricularia (Lentibulariaceae) in which it is often impossible to
distinguish organs
corresponding to any of leaf, steam, or root. The pre-evolutionary
morphologists,
with their a priori notions of the fundamental nature of the categories
leaf, stem
and root, felt that the ideal angiosperm would naturally display these
organs in their
purest, most unsullied form. Thus pre-evolutionary doctrine regards these
plants and their organs as degraded - to the extent that in them the pure
morphological categories are no longer recognisable. That these plants must
cause discomfort is evidenced by the infrequency with which they are
discussed and illustrated."

John Grehan

Croizat, L. (1961). Principia Botanica. Published by the Author, Caracas

Heads, M. J. (1984) Principia Botanica: Croizat's contribution to botany.
Tuatara 27,     26-48.