130 MISSOURI BOTANICAL GARDEN. 
ARIOCARPUS FURFURACEUS (Watson). 
Mamillaria furfuracea, Watson, Proc. Amer. Acad. 265: 150. 1890. 
Anhalonium furfuraceum, (Watson) Coulter, Contr. U. 8. Nat. Herb. 
8: 180. 10 June, 1894. 
This species seems to have never before been figured. 
Our plate is from a photograph of a plant received in the 
collection of Mr. J. A. Becker, before mentioned, under 
the name Anhalonium prismaticum, but a comparison with 
Dr. Watson’s description as well as with his type material 
(Pringle no. 2580, 1889) leaves no question of doubt but 
that it is the Watson species. The characteristic flatness 
of the head is clearly shown as well as the slight wrinkling 
of the triangular upper surface of the tubercles. Another 
feature which is prominent in both the type specimen and 
our own plant is the peculiar bronze appearance of the 
surface of the tubercles. In comparison with A. retusus 
this species has a comparatively shorter tubercle, the upper 
surface of which is more nearly equilateral triangular. — 
Plate 34. 
ARIocARPUS RETUSsUS, Scheidw. Bull. Acad. Royal des 
Sciences de Bruxelles 5: 492. J pl. 1838. 
Mamillaria prismatica, Lem. Hort. Univ. 1: 281. 1839. 
Anhalonium prismaticum, Lem. Cact. 1. 1839,— Blanc, Catal. and Hints 
on Cacti 12,no.7. 1888 [2nd ed.].— Bot. Mag. iii. 49. pl. 7279, 
1893.— Baltimore Cactus Journ. 2: 266. 7 fig. Feb. 1896. 
Anhalonium retusum, Salm-Dyck, Cact. Hort, Dyck. 15, 1845. 
Cactus prismaticus, Kuntze, Rev. Gen. Plant. 261. 1891. 
This species is the oldest and, next to A. fissuratus, per- 
haps the most common in cultivation. A quite full de- 
scription with a good plate showing the plant in natural 
size were first published by Scheidweiler and this publica- 
tion forms the basis for the type of both the genus and 
this species. It seems, however, from the different publi- 
cations, that the species is very variable in form, and this 
variation is well marked in those illustrations which have 
been published. Considering Scheidweiler’s figure as the 
type, — and, in my judgment, it is a good medium of 
the forms,— we may with advantage compare the others 
