434 Ill. SEGREGATES AND 
undiverged parent species. But all of them have held their 
ground or water through editions five and six, without extinguishing 
each other. In this last edition they are even placed in living 
competition with an eighth divergence under name of pseudo- 
fluitans, given to our ancient friend heterophyllus when better 
adapted to external circumstances by elongating its growth and 
shape in running water. This being a state of aquatilis which had 
often been mistaken for true fluitans, the name is apt enough. 
The Author of the ‘ Manual’ assigned the sponsorial paternity of 
this eighth species to Mr. Newbould ; but he omits to tell us from 
which one of his own adopted species in former editions this 
eighth one had diverged by natural selection, or had been excised 
by botanical art 
The first volume of ‘ English Botany,’ edition third, bears date 
one year after the fifth edition of the ‘Manual.’ Mr. Boswell- 
Syme keeps up the ancient name aquatilis to fit an aggregate or 
super-species, which is divided into four “sub-species,” namely, 
peltatus, heterophyllus, Drouwetit, and trichophyllus ; all of them 
being names and species of the ‘Manual’; but the first of these 
four being re-composed of the peltatus and floribundus (with 
pseudo-fluitans), admitted into the ‘ Manual’ as distinct species. 
This may be regarded as a case of orthodox convergence, rapidly 
supervening upon heterodox divergence. The other two species 
of the ‘Manual’ are represented by Baudotii as a type, with 
confusus for its subvariety. The eight species of the ‘Manual’ 
thus are represented in ‘ English Botany’ by five species or sub- 
species and three subordinate varieties. So that, at any rate, 
these two good authorities for British plants agree in recognizing 
eight forms, more or less separable, of our familiar friend 
aquatilis ; while they differ widely in the varietal or specific rank 
which they assign to the plants. 
Having small faith indeed in these eight alleged species, I 
should really have preferred to continue the opposite extreme of 
Mr. Bentham’s ‘ Handbook,’ where all are converged into one, if 
that extreme did not also involve the necessity for re-sinking the 
long recognized fluitans and circinatus ito varieties of aquatilis, 
