MONOGRAPH OF THE GENUS PYROLA. 221 
amine the several new species contained in that splendid 
collection. 
The genus Pyrola belongs to the natural order Ericea, 
as now constituted, comprizing the ErioE and Rhododeiu 
dra of JussiEU, and to the section of true Ericece^ from 
which it would be unnatural to exclude the VaccmeiE of M. 
De Candolle. The Monotropea, another section of Eri^ 
cea, first proposed by Mr Nut tall, in his Genera of North 
American Plants, consist of Monotropa and Hypopithys 
(which ought tobe again united loMonotropayhemg not suffi- 
ciently distinct from it), and his new genusPterospora. These 
in many respects approach near to Pyrola, both in habit and 
characters, and especially as there is a leafless species of Py- 
rola ; but the manner of emitting their pollen is totally dif- 
ferent, not being by pores, but by lateral fissures. The 
anthers of Monotropa are not, as Mr Nut tall has sup- 
posed, unilocular, although, after shedding their pollen^ 
and from the peculiar mode of emitting it, they appear to 
be so : they are flat and circular, furnished with two very 
short obtuse horns at their base, and emit their pollen 
by two transverse fissures on their internal surface. Those 
of Pterospora, on the contrary, shed their pollen by longi- 
tudinal fissures, and have two very long subulate horns at 
their base. This plant appears to be the link between these 
two sections. 
The whole genus being perfectly natural, I have pre- 
ferred retaining it entire. I have separated the whole into 
two divisions, and these I have again subdivided into sec- 
tions. The first division contains the largest portion of the 
species, consisting of those the valves of whose capsules be- 
gin first to open at the base, with their margins connected 
with an intricate fine tomentum, with alternate leaves, and 
