Q: Aldrovanda: various types
A: There is only
one species in this genus, and it is Aldrovanda vesiculosa L.
Turion I
Turion II
Having grown different geographic strains of this species, I have observed significant differences
in their forms---plants from some locations are bushier than
others, some strains are comparatively more slender. Plants from temperate areas form turions
(dormant buds) during the winter and can withstand winters where the water
freezes over for many months! Others from warmer climes grow year-round but
will form buds if given a wintery chill. Look at the two turion photos to the right,
and you can see how even in dormancy these two strains look different.
Five different infraspecific names
have been given to this species:
Aldrovanda vesiculosa L. var. vesiculosa
Aldrovanda vesiculosa var. australis Darwin
Aldrovanda vesiculosa var. duriaei Caspary
Aldrovanda vesiculosa var. rubescens A.T. Cross & Adamec
Aldrovanda vesiculosa var. verticillata(Roxb.) Darwin.
Shoot
Mouth
Having said all this, genetic studies indicate that there is not much genetic diversity in the genus, so those names
really don't merit being used.
Carnivorous plant horticulturists, however, thrill to grow one of the two known strains of "red"
Aldrovanda vesiculosa from Australia. These plants are deep red or even purplish when
grown in bright sun. Muy bonita! This is the plant that was recognized under the name
Aldrovanda vesiculosa var. rubescens. However, if you don't think that this minor
mutation merits a varietal rank, then you can disregard the name.
The fossil record of Aldrovanda has been studied extensively. The
fossils are typically of its seed (although we know of
one case of a fossilized leaf). By studying the fossil
seeds, paleobotanists have discovered many ancient (but now extinct) species
of Aldrovanda.
Page citations: Breckpot, C. 1997; Cross, A.T. 2012;
Degreef, J.D. 1997;
Rice, B.A. 2006a; Lowrie, A. 2013; Schlauer, J. 1997, 2002; Thiele, K. R., & Coffey, S.C. 2014; personal observations.
