66 THE CACTACEAE. 



Very variable, sometimes low and spreading from the base and forming broad clumps, at other 

 times 5 to 6 dm. high, with a more or less definite woody stem and numerous lateral branches; joints 

 easih- detached, sometimes short and nearly globular to narrowly oblong, lo to 15 cm. long, strongly 

 tuberculate; spines reddish, normally 6 to 10, elongated, 4 to 5 cm. long, covered with thin, white, 

 paper}^ sheaths ; flowers 3 cm. long, yellow; petals obtuse; ovary often bearing long spines at the 

 areoles, but usualh^ naked. 



Type locality: In Mexico. 



Distribution: Highlands of central Mexico; also in Ecuador, Peru, and northern Chile. 



Opuntia stapeliae has long puzzled collectors and students of cacti. We are convinced 

 now that it is only star\-ed or stunted greenhouse specimens of the common O. tunicata. 

 When grown in cultivation, 0. tunicata takes on abnormal shapes, for the joints, which 

 break oflt easily, rarely grow to their full size. In its native home many small dwarf plants 

 are found even,Tvhere about the larger plants. We have discussed this explanation of 

 0. stapeliae with Mr. A. Berger, and he agrees with our conclusion. 



No specimens of the type of 0. stapeliae are preser\^ed in the De CandoUe Herbarium. 

 The plant figured as Opuntia stapeliw (?) by Goebel in Pflanzenbiologische (f. 36) does not 

 belong here. It is erect, has strongly tuberculate joints, very short spines and narrow 

 elongated leaves. 



Cereus tunicatus (Pfeiffer, Enum. Cact. 170. 1S37) is given as a synonym of Opuntia 

 tunicata, but has never been formally taken up. 



We. believe Opuntia hystrix Grisebach, collected by C. Wright in Cuba, belongs here, 

 probabl}' being an escape from a garden. Dr. Rose examined the specimens in the Krug 

 and Urban Herbarium in Berlin in 1912; the loose sheaths of the spines of these specimens 

 are now brown, while the flowers seemed a little smaller than those of the Mexican speci- 

 mens. The flowers were described as red. 



Opuntia Juriosa Wendland (Pfeiifer, Enum. Cact. 170. 1837) is referred to 0. tunicata 

 by Pfeiffer, while Sakn-Dyck refers it to his variety 0. tunicata laevior (Cact. Hort. Dyck. 

 1849. 73. 1850). 



Illustrations: Bull. U. S. Dept. Agr. 31 : pi. 4; Cact. Journ. i : October; The Garden 62 : 

 425; Safford, Ann. Rep. Smiths. Inst. 1908: pi. 10, f. 5; Schumann, Gesamtb. Kakteen f. 2; 

 Rep. Mo. Bot. Gard. 22 : pi. 13, 14, these two as Opuntia perrita. 



Plate X, figure i, represents a joint of a plant collected by Dr. Rose near Cuzco, 

 Peru. Figure 80 is from a photograph of the same plant. 



28. Opimtia pallida Rose, Smiths. Misc. Coll. 50: 507. 1908. 



Stems 5 cm. in diameter, about i meter high, with widely spreading branches, the whole plant 

 often broader than high ; old areoles ver^- spiny, often bearing 20 spines or more, often 3 to 4 cm. long, 

 ^vith white, paper}- sheaths; young areoles bearing few spines; ovary tuberculate, the areoles 

 either naked or bearing a few bristly spines; flowers pale rose-colored; petals 15 mm. long. 



Type locality: Near Tula, Hidalgo, INIexico. 



Distribution: State of Hidalgo, Mexico. 



This species is known only from near Tula, Mexico, where it was discovered by Dr. 

 J. N. Rose in 1905, and afterwards collected near the same station by Mr. E. W. Nelson. 

 It grows interspersed with 0. imbricata, but is much lower in stature and has smaller leaves 

 and lighter-colored flowers. It is much like 0. tunicata, but that species has yellow flowers 

 and is always smaller. 



Illustration: Contr. U. S. Nat. Herb. 10: pi. 17, a. 



Figure 81 is from a photograph of the type specimen. 



29. Opuntia molesta Brandegee, Proc. Cal. Acad. II. 2: 164. 1889. 



Stems I to 2 meters high, or in cultivation only 6 dm. high, with few, long, spreading branches ; 

 joints clavate to subcylindric, 10 to 40 cm. long, sometimes as much as 4 cm. in diameter at the top, 



