20 
marked species, and was the result of a summer^s 
study of that plant in its various stages of 
growth. After briefly describing Nymphoea alha 
the white water lily, he said—Some years ago I 
collected and mounted specimens of Nuphai lutea 
and Nupjliar pumila, but was not aware till early 
this summer that any doubt was entertained as to 
the just title of N. pumila to rank as distinct from 
N. lutea. Conversing with botanists in England, 
and here too, on the subject, I w-as surprised to 
find they considered N. pumila a small variety of 
A. lutea. This induced me to pay several visits to a 
loch in which both plants abound, and to compare 
the two. I found that in the descriptions of the 
plants given in most Florse, ma,ny important charac¬ 
teristics are too lighly commented on, while some of 
less importance and perhaps questionable persistency 
are brought forward too prominently. Nuphar 
pumila is inv^ariably found growing in lochs or ponds, 
and seems to prefer a sandy bottom to root in. N. 
lutea though sometimes growdng in still water, is most 
generally found in running streams and ditches, and 
always rooting in mud. The difference in size is the 
most striking distinction— N, lutea being the largest 
b^^ more than one half. Size and colour are not to be 
always relied upon in derermining species, but wnen 
always persistent, possess a certain value. Had two 
plants so different, growing together, and subject 
to the same condition, been the extreme forms 
of one and the same species, we should have 
expected to find intermediate gradations. These do 
not occur ; and the late Curator of the Glasgow 
Botanic Gardens grew N. pumila for many years 
there, and never found it vary in size. Of some 
hundreds I examined, the variation was not more 
than J of an inch. The colour of the plants is almost 
the same— pumila perhaps being more of a deep 
green. The colour of the stem, as seen by any one 
wading amongst the plants, is very different—those 
of lutea are of a sober green, while those of pumila are 
of a beautiful deep reddish brown. The most im¬ 
portant difference betw^een the two plants is in the 
form of the stigma. All the members of this order 
