e;scobaria. 53 



3. Neobesseya missouriensis (Sweet). 



Cactus mamniillaris Nuttall, Gen. PI. i: 295. 1818. Not Linnaeus, 1753. 



Mammittaria missouriensis Sweet, Hort. Brit. 171. 1826. 



Mammillaria simplex Torrey and Gray, Fl. N. Amer. i : 553. 1840. 



Mammillaria nultallii Engelmann, PI. Fendl. 49. 1849. 



Mammillaria nuttallii borealis Engelmann, Proc. Amer. Acad. 3: 264. 1856. 



Cactus missouriensis Kuntze, Rev. Gen. PI. i: 259. 1891. 



Mammillaria missouriensis nuttallii Schelle, Handb. Kakteenk. 241. 1907. 



Coryphantha missouriensis Britton and Rose in Britten and Brown, Illustr. Fl. ed. 2. 2: 570. 1913. 



Plants solitary or cespitose, globose, 2.5 to 5 cm. in diameter; tubercles more or less spiraled, 10 

 to 15 mm. long; spines 10 to 20, acicular, gray, pubescent, all radial or sometimes i central; flowers 

 greenish yellow; outer perianth-segments narrowly oblong, gradually tapering to an acute apex, 

 ciliate; inner segments linear- lanceolate, attenuate; fruit globose, scarlet, about i cm. in diameter; 

 seeds i mm. in diameter. 



Type locality: On the high hills of the Missouri, probably to the mountains. 



Distribution: North Dakota to Montana, Colorado to Kansas, Oklahoma, and perhaps 

 northern Texas. 



This little cactus has a wide distribution on the Great Plains; both its conspicuous 

 yellow flowers and its round red fruits are very attractive. 



Coryphantha nuttallii, credited to Engelmann, is cited as a synonym of Mammillaria 

 nuttallii by Riimpler (Forster, Handb. Cact. ed. 2. 407. 1885). 



Illustrations: Meehan's Monthly 10: pi. 3; Gartenwelt i: 85, as Mammillaria mis- 

 souriensis; Gartenwelt i: 89, as M. missouriensis viridescens; Britton and Brown, Illustr. 

 Fl. 2: f. 2525, as Cactus missouriensis; Schelle, Handb. Kakteenk. 241. f. 160, as M. 

 missouriensis nuttalliii; Cact. Mex. Bound, pi. 74, f. 6, as M. nuttallii borealis; Blanc, Cacti 

 72. No. 1426; Bliihende Kakteen 3: pi. 145, as M. nuttallii; Britton and Brown, Illustr. 

 Fl. ed. 2. 2: f. 2984, as Coryphantha missouriensis. 



Plate XI, figure 4, shows a plant from a large clump sent by Professor C. O. Chambers 

 in 1921 from Stillwater, Oklahoma. 



4. Neobesseya notesteinii (Britton). 



Mammillaria nolesleinii Britton, Bull. Torr. Club 18: 367. 1891. 



Cactus notesteinii Rydberg, Mem. N. Y. Bot. Gard. i: 272. 1900. 

 Oval, solitary or cespitose, about 3 cm. in diameter; tubercles nearly terete, about 6 mm. 

 high; spines 12 to 18, white, turning gray, weak, slender, 8 to 12 mm. long, pubescent throughout, 

 a central one usually present and frequently pink-tipped; flowers 15 to 25 mm. broad, ash-gray, 

 tinged and penciled with pink, the segments broadly linear-oblong, mucronate; fruit obovoid; 

 seeds black, globose, pitted. 



Type locality: Near Deer Lodge, Montana. 



Distribution: Known only from the type locality. 



Professor F. N. Notestein, who first collected and observed this little cactus, found it 

 in gravelly soil near a small creek ; it differs from the other species of the genus in the color 

 of the flowers and the more pubescent spines. 



8. ESCOBARIA gen. nov. 



Globose or cylindric, usually cespitose cacti, never milky; tubercles grooved above, persisting 

 as knobs at the base of old plants after the spines have fallen; spines both central and radial, never 

 hooked; flowers small, regular, appearing from top of plant at bottom of groove of young tubercles; 

 stamens and style included; fruit red, naked (or with one scale), indehiscent, globular to oblong, 

 crowned by the withering perianth; seeds brown to black; aril basal or subventral, oval. 



Type species: Mammillaria tuberculosa Engelmann. 



The two species of this genus known to Schumann were placed by him in the subgenus 

 Coryphantha of Mammillaria ; they are like the Coryphanthae in having grooved flower- 

 bearing tubercles, but are otherwise different, especially in the flowers, fruit, and seeds. 



Eight species are known from northern Mexico and southern Texas. 



The genus commemorates the work of two distinguished Mexicans, the Escobar 

 brothers, Romulo and Numa, of Mexico City and Juarez. 



