Dj. Crawford et al., AN ALLOZYME STUDY OF 2 SIBLING SPECIES OF LEMNA (LEMNACEAE) WITH COMMENTS ON THEIR MORPHOLOGY, ECOLOGY AND DISTRIBUTION, Bulletin of the Torrey Botanical Club, 123(1), 1996, pp. 1-6
Enzyme electrophoresis was employed to examine divergence between Lemn
a minuta H.B.&K. and valdiviana Phil., two nearly indistinguishable sp
ecies comprising sect. Uninerves of Lemna. Fifteen presumptive loci we
re resolved for 25 clones of Lemna minuta and 26 of L. valdiviana. Gen
etic identity between the two species is 0.70, which is near the mean
value for congeneric species of flowering plants, but is much higher t
han values reported for other species of Lemnaceae. With the exception
of two clones, the taxonomic designations of the strains correlated w
ith monomorphism for alternative alleles at two MDH loci. The two spec
ies are highly differentiated at two other loci as well. Although the
tars are morphologically similar, they differ in geographic distributi
on, flavonoid chemistry, and certain physiological and ecological attr
ibutes. The relatively high identity at allozyme loci compared to othe
r Lemnaceae suggests that L. minuta and L. valdivina are closely relat
ed and recently diverged sister species.