VOL. 5] Recent Literature. 15 
character of flowering from the depressed summit, and place 
them as a section in Phyllacanthus. 
In the Opuntize a more natural sequence would seem to be 
Peireskia, Maihuenia, Pereskopuntia Pterocactus, Cylindropun- 
tia, Platopuntia, Nopalea. Mahuenia attributed to Phillippi but 
no reference given, and no species credited to him, appears to me 
better as a section of Pereskia. Pereskopuntia might, perhaps, 
include Pterocactus, the ovary being buried in the fruit-bearing 
branch, in both; at least it is so in the Pereskopuntias Porteri and 
Brandeget. 
The proposed division of Cereus by reinstating with altered 
boundaries the old genera Cephalocereus and Pilocereus cannot 
well be carried out. The plants so brought together are quite 
heterogeneous. 
Echinocactus as at present received is a somewhat confused 
assemblage, some of its members too closely connected with 
other genera. By their fruits and seeds, when they are 
better known, it may be possible to improve the generic bound- 
aries. 
The sections of or subgenera are still poorly defined. The 
lactescent species are often difficult, and in herbarium specimens 
impossible to discriminate. A considerable number of the species 
in Dr. Schumann’s § Aydrochylus undoubtedly have milky juice. 
Of those which have latex only in the body of the plant discrim- 
ination is sufficiently difficult even in life, for the amount seems 
to vary greatly with the state of growth. 
The subgenus Coryphantha is divided into two sections, Aula- 
cothelaze and Glanduliferze, by the presence or absence of glands 
in the axil or groove, only five of the twenty-two species being 
credited with them, while as a matter of fact they can be 
demonstrated in most of the other species. 
T’here are occasional errors in citation, quite pardonable con- 
sidering the number of references, A curious instance of con- 
fused reference is found at the foot of page 495, where he finds it 
very strange that Coulter could not find 47. dazmonoceras, for “‘it 
is to be found on the same page with J/, ‘mpexicoma, which he 
cites, and Prince Salm-Dyck quite correctly, l. c. 131, quoted.” 
