117 
* * Flowers red. 
+ Central spine solitary or sometimes wanting. 
51. Cactus dasyacanthus (Engelm.) Kuntze, Rev. Gen. PI. 259 (1891). 
Mamillaria dasyacantha Engelm, Syn, Cact. 268 (1856). 
Subglobose, 3.5 to 6.5 em. high, simple: tubercles slender and terete, 
spreading, lightly grooved even to the base, 8 to 10 mm, long: radial 
spines 30 to 50, mostly in two series, straight and loosely spreading, 
the exterior ones (25 to 35) capillary and white, 6 to 18 mm. long, the 
interior ones (7 to 13) stiffer (setaceous), longer and darker and black- 
tipped; the central spine straight and porrect, 12 to 20 mm. long, often 
wanting: flowers small, red: fruit ovate, small (8 to 10 mm. long?): 
seeds globose-angled, almost black, pitted, 0.8 to 1:2 mm. long (Zl. 
Cact. Mex. Bound. t. 12. figs. 17-22)—Type, Wright 110 in Herb. Mo. 
Bot. Gard. 
From Eagle Pass, Texas, westward to El Paso and southern New 
Mexico, and southward into Chihuahua, 
Specimens examined: TEXAS (Wright 110 of 1852): NEw MrExtco 
(Vasey of 1881; Mearns of 1802, in Big Hatchet Mountains): CHInUA- 
HUA (Pringle 251 of 1885, in part). 
Pringle 251 as distributed to Nat. Herb. is C. tuberculosua. 
52. Cactus maculatus, sp. nov. 
Obovate-cylindrical, 6 by 8em.,somewhat cespitose: tubercles ovate, 
terete, 10 min. long, grooved to the base, with naked axils: radial 
spines 10 or 11, straight and spreading, rigid, blackish (becoming ashy 
with age), black-tipped, 12 mm. long; central spine large, more or less 
spotted, erect, 25 to 35 mm. long: tlower 13 mim. long, pinkish: fruit 
unknown.—Type in Herb. Coulter. 
San Luis Potosi. 
Specimens examined: SAN Luis Porost (Hschanzier of 1891). 
Somewhat resembles C. tuberculosus in general appearance, but very different in 
spine characters. 
53. Cactus brunneus, sp. nov. 
Obovate-cylindrical, 3 by 6 em., simple: tubercles ovate, grooved te 
the base, 5 to 6 mm. long, with woolly axils: radial spines 11 to 15, 
spreading, rather rigid and brownish (lighter with age), 8 to 10 mm. 
long; central spine much larger, 20 mm. long, hooked: flower and fruit 
unknown.—Type in Herb. Coulter. 
San Luis Potosi. 
Specimens examined: SAN Luis Povosr (Lschanzier of 1591), 
+ + Central spines 3 to 12. 
54. Cactus conoideus (DC.) Kuntze, Rev. Gen. PI. 260 (1891). 
Mamillaria conoidea DC. Rev. Cact. 112 (1529). 
Mamillaria strobiliformis Engelm., Wisliz. Rep. 113 (1848), not Scheer (1850). 
Ovate-conical, 3.5 to 10 em. high, 4 to 7 em. in diameter below, with 
densely woolly vertex, simple: tubercles conical, about 12 mm. long, 
