266 Rhodora [NOVEMBER 
broad one appearing in Drosera binata. This remarkable Australian 
species has leaves which sometimes attain a height of more than 
two feet. The blades are described as “ 2-forked,” or “divided to 
the base into two long linear lobes.” In reality the blade is entire. 
and is extraordinarily broadened, so that it extends transversely to 
the main axis of the leaf into two linear arms. ‘These arms are 
turned upward and give the two-forked appearance. Of the same 
type is the little New Zealand Drosera flagellifera. 
The above enumeration omits a few ambiguous — or for present 
purposes negligible — species. However, it fairly represents the 
genus, and will serve to illustrate the distribution of leaf-forms 
amongst the species. 
The prominent types arrange themselves naturally in a series, 
beginning with the filiform, thence passing, by means of the elon- 
gated spatulate, to the rounded ; then, by the accentuation of breadth, 
advancing through or near the crescent-shaped to the so-called two- 
forked. ‘The series might represent a single line of evolution, with 
the point of origin at one end or'the other; or the series may com- 
prise two lines of development, having a common starting point in 
the round leaved group. Considering the course to have been a 
simple one, it is conceivable that the extremely broad may represent 
the primitive condition. But this supposition is improbable, upon the 
face of it, because the given form is so unusual in plants ; it is in 
fact unique. The D. binata type seems to be terminal rather than 
original. Or Drosera filiformis, at the other end of the line, may, 
stand for the archetype. Three of the genera of Droseraceae have 
leaves of nearly the same description as those of D. filiformis, except 
as to the structure of the glandular hairs. ‘The number of linear- 
leaved species of Drosera, however, is small; and furthermore, on 
grounds which cannot here be stated, two of these should be excluded 
from consideration in this connection. We have left six species which 
may be modern representatives of an original Drosera stock. But 
the filiform condition as seen in Drosera filiformis again, is unusual 
in plants and looks rather like the product of special evolution than 
like a stock-form. It might readily have been derived from the 
rotund by steps which to-day are preserved in Drosera longifolia and 
linearis. 
The rounded style— under which I include the forms like or 
approaching that which obtains in Drosera rotundifolia — is clearly 
