132 MISSOURI BOTANICAL GARDEN. 
LOPHOPHORA.* 
Plants simple or cespitose, depressed-globose to top- 
shaped or even short clavate, ribbed. Ribs bearing in- 
conspicuous low tubercles on the summits of which 
appear the flower-bearing areolae. Areola round, spine- 
less and bearing a tuft of straight, moderately long, silky 
hairs. In the presence of the ribs with the areolae dis- 
tributed upon them in regular order, this genus approaches 
more nearly to Cereus or Echinocactus, and to the latter it 
has been referred by some authors. From a study of the 
vegetative character my conviction is that it constitutes a 
well defined genus. It differs from Echinocactus in hav- 
ing but the one kind of areola, and this always circular in 
outline, and in the total absence of spines. Furthermore 
the plant is more succulent in growth than in that genus. 
In these characters it is even further removed from 
Mamillaria and Ariocarpus. Its nearest relationship seems 
to be to the mamillate forms of Echinocactus. 
LopHorpHora Wituiamsi (Lem.) Coulter, Contr. U. S. 
Nat. Herb. 3: 131. 10 June, 1894. 
Echinocactus Williamsii, Lem. in Allg. Gart. Zeit. 18: 885. 1845. — 
Bot. Mag. iii, 8. pl. 4296. 1847. — Monats. fiir Kakteenk. 4: 37. 
Z fig. 20 March, 1894. 
Anhalonium Williamsii, Lem. in Férster’s Handb. Cact. 233. 1886. 
{ed. Riimpler].— Blanc, Catal. and Hints on Cacti 13, no. 3. Jan. 
1888 [2nd ed.].— Gartenflora 87: 411. fig. 5. 1 Aug. 1888, — 
Baltimore Cactus Journ. 2: 247. 7 fig. Jan. 1896. 
The characteristic form and habit of growth in this 
species are well portrayed inthe accompanying plate. The 
illustration is from one of the largest plants and shows the 
characteristic convex, almost unbroken ribs. The division 
of these ribs into rows of tubercles is indicated only by a 
faint, short, horizontal line just below each areola and in 
some instances by the slightly sinuous direction taken by 
the groove between the ribs, though commonly this is, 
* Coulter, Contr. U. S. Nat. Herb. 8: 131. 10 June, 1894. 
