208 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
be the species best known. In the " N. American Flora," Rose's 
descriptions of praealtum and confusum are evidently copied from 
Hemsley, "Biol. Centr. Americana," and he even says of the former, 
" a very doubtful species." His description of dendroideum, on the 
other hand, is clearly original, though whether based on Uving or 
dried material does not appear. 
The descriptions are not sufficiently full to point to satisfactory 
distinguishing characters of flower between this species and the other 
two, but it appears easily separated by its leaves (see fig. 119), which 
Fig. 118. — 5. dendroideum M09. and Sesse. 
are distinctly stalked and have a nearly orbicular lamina. In my 
plant, also, they have a whitish margin when young {due to a waxy 
secretion) and a purplish margin when old, while in the two other 
species the leaves are wholly green ; the leaf also is of much firmer 
texture than in praealtum or confusum, and the stem is stiff and 
erect, with few ascending branches, while in the others it branches 
frequently and soon forms a low bush. The petals, described as 
lanceolate, appear to be broader than those of praealtum, narrower 
than those of confusum. The inflorescence is large like that of 
praealtum, not congested as in confusum. In the following description 
the stem and leaf characters are taken mainly from my living plant, 
the remainder from De Candolle, Hemsley, and Rose. To judge 
