48 THE CACTACEAE. 



been much discussion about the identity of the plant; Coulter transferred it to Ceretis, 

 referring to it Ccrcus coccineus and C. phoeniceus and assigning to it a wide range, Colorado 

 to San Luis Potosi. Rydberg transferred the name to Echinocereus but appUed it to the 

 same group of plants described by Coulter. A careful restudy of the original illustration 

 and Engelmann's description and a restudy of all the cacti of similar habit in the southwest 

 leads us to a different conclusion from that reached by Dr. Coulter and Dr. Rydberg. 

 Engelmann, who described it as a Manwiillaria, says that it appears to be aUied to 

 il/. vivipara, and this we beUeve is its true relationship. A MammiUaria from the region 

 about Flagstaff often forms the great clusters mentioned by Engelmann, and while we 

 believe that it differs from the one found in northern Arizona it is certainly a near ally, 

 probably representing the closely related species from southeastern Arizona and south- 

 western New Mexico which has often passed as M. arizonica. 



Engelmann referred a specimen which he had from Sonora to his variety MammiUaria 

 vivipara neo-mexicana with the remark that it was "a form with more spines than any 

 other." 



Plate IV shows a clump sent by ISIrs. Ruth C. Ross from near Aravaipa, Arizona, in July 

 1922. Figm-e 47 is from a photograph of a single plant obtained by Dr. Rose near Benson 

 May I, 1908, which afterwards flowered in Washington. 



36. Coryphantha cubensis Britton and Rose, Torreya 12: 15. 1912. 



MammiUaria urbaniana Vaupel, Monatsschr. Kakteenk. 22: 65. 1912. 

 Plants depressed-globose, tufted, 2 to 3 cm. broad, pale green; tubercles numerous, vertically 

 compressed, 6 to 7 mm. long, 4 to 5 mm. wide, about 3 mm. thick, grooved on upper side from apex 

 to below middle, the groove ver}' distinct; spines about 10, whitish, radiating, acicular but weak, 

 3 to 4 mm. long, those of young "tubercles subtended by a tuft of silvery- white hairs, 1.5 mm. long; 

 flowers pale yellowish green, 16 mm. high, the segments acute; filaments, style, and stigma-lobes 

 yellowish; fruit red, less than i cm. long, naked; seeds black, somewhat angled. 



Type locality: Among stones in barren savanna, southeast of Holguin, Oriente, Cuba. 



Distribution: Type locality and vicinity. 



This species is very inconspicuous and perhaps for that reason is rare in collections. 

 It has only twice, to our knowledge, been collected, both times by Dr. J. A. Shafer, once in 

 1909 (No. 2946) and again in 1912 (No. 12432), who gave a short account of its discovery in 

 the Journal of the New York Botanical Garden (No. 155). He states that it barely pro- 

 trudes through the layer of broken stones that filled the interstices between the larger 

 rocks; that the largest plants were scarcely an inch in diameter, one of them bearing a 

 small yellowish flower. It lives only a short time in greenhouse cultivation. 



On account of the name MammiUaria cubensis Zuccarini (Labouret, Monogr. Cact. 59. 

 1853) Vaupel gave a new specific name to the plant when he transferred it from Cory- 

 phantha. 



Plate v, figure i, shows the plant collected by Dr. Shafer in 1912 which flowered in the 

 New York Botanical Garden in July of the same year; figure \a shows the fruit and figure ib 

 shows a tubercle from the same plant. 



37. Coryphantha sulcata (Engelmann). 



MammiUaria sulcata* Engelmann, Bost. Journ. Nat. Hist. 5: 246. 1845. 



MammiUaria sirobiliformis Muhlenpfordt, AUg. Gartenz. 16: 19. 1848. Not Engelmann, 184S. 



MammiUaria calcarata Engelmann, Bost. Journ. Nat. Hist. 6: 195. 1850. 



Coryphantha calcarata Lemaire, Cactees 35. 1868. 



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



Cactus scolymoides sulcatus Coulter, Contr. U. S. Nat. Herb. 3: 116. 1894. 



MammiUaria radians sulcata Schiunann, Gesamtb. Kakteen 496. 1898. 



Cactus sulcatus Small, Fl. Southeast. U. S. 812. 1903. 



Cespitose, 8 to 12 cm. in diameter; tubercles rather large, 10 to 12 mm. long, somewhat flat- 

 ened, soft; radial spines acicular, straight, white; central spines several, one somewhat stouter 



* Forster (Haudb. Cact. 255. 1846) credits such a name to Pfeiffer but it is \vithout description. 



