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R. H. Compton. 
a small point it contributes to the support of the view that bladder 
and utricle should not be homologised. 
A more important argument, which, however, appears to have 
been overlooked in previous discussions, is derived from the existence 
of a South American species of Genlisea, G. filiforiuis. This plant 
was described by A. St. Hilaire 1 in 1833, and later authors have to 
a large extent copied the description with its imperfections. 
Darwin, 2 however, recorded the fact that G. filiforniis does not bear 
the typical utricles found in the other species, but on the other hand 
bears on its rhizomes a number of typical Utricularian bladders : 
these he considered to shew signs of reduction on account of their 
small size and the fewness of their absorptive hairs. Darwin asks: 
“ What are we to infer from these facts ? ” It appears clear that a 
just inference is that the typical utricles of Genlisea are not 
homologous with the bladders of G. filiformis and of the species of 
Utricularia. 
As it thus appears that the argument from the leaf-nature of 
the Genlisea utricle is untrustworthy, even if not untenable, let us 
examine the actual facts in regard to Utricularia itself more on 
their merits. 
There can be no doubt that the small bracts on the peduncle of 
Utricularia are true phyllome structures. It seems to be a general 
principle that the peduncle is, relatively to the rest of a plant, 
primitive in structure: and since the bracts of the Utricularia 
peduncle agree so closely with similar structures in more “ normal ” 
plants, the conclusion that they are of phyllome nature is irresistible. 
Now Schimper 3 described leaf-like organs arising in the axils of the 
peduncular bracts of U. cornuta. He remarks, “ Wahrscheinlich 
ist es mir daher, dass die sogenannten Blatter Kaulomnatur 
besitzen.” The biological significance of this fact is clearly that 
leaf-like structures are only formed in air, and that a runner of the 
Utricularia type would be quite useless in such a position. 
In some species (e.g., U. orbiculata) the embryo bears two 
papillae, which are sometimes homologised with cotyledons : these 
may grow out into runners, and hence it is concluded that the 
runners are derived from cotyledons and therefore from foliage 
leaves. But it must be remembered that the homology of cotyledon 
and foliage-leaf is still a matter of dispute: and what is more 
1 Voyage an District des Diamans, II., p. 428. 
2 Insectivorous Plants, p. 364. 
3 Bot. Zeit., 1882, p. 243. 
