4 o 



THE CACTACEAE. 



Common in the dry parts of Bahia, Brazil, where it was collected by Rose and Rus- 

 sell in 1915 (No. 19723, type). Dr. Zehntner thinks there may be a second species, as he 

 has found one with purple flowers; specimens from southern Bahia had purple buds, but 

 the open flowers were not seen. The type comes from Joazeiro, northern Bahia. 



Dr. Rose studied this species in the field and believed it to be new. On reaching 

 Rio de Janeiro, he found that Dr. A. Lofgren had also studied it, referring it, however, 

 to Opuiitia, using the above specific name. 



Figures 45 and 46 are copied from drawings of the flowers given to Dr. Rose by Dr. 

 Lofgren ; figures 47 and 48 are from twigs of the plant grown at the New York Botanical 

 Garden; figure 49 is from a photograph of the type plant. 



5. MAIHUENIA Philippi, Gartenflora 32: 260. 1883. 



Plants low, cespitose, often forming small, dense mounds; stems jointed; joints small, globular 

 or short-cylindric; leaves small, usually terete, persistent; leaves of seedlings terete, ascending, 

 with 2 long white bristles in the axils; areoles filled with white wool; spines 3, the central one 

 elongated, the 2 lateral ones small and very short; glochids wanting; flowers large for the size of the 

 plant, yellow or red, usually terminal; petals distinct; flower-tube none; stamens and sty'e much 

 shorter than the petals; fruit juicy (described as dry in one species), oblong to obovoid, bearing 

 small scattered, ovate, persistent leaves; wall of fruit thin; cotyledons linear; seed black, shining, 

 with a brittle testa. 



FIG. 50. Maihuenia valentinii. 



Type species: Opnntia pocppigii Otto. 



There are five species described, rather closely related, natives of the high mountains 

 of Chile and Argentina. 



The generic name is derived from maihuen, the native name of the plant. 



This is a small, localized genus; it is perhaps nearest Opuntia, but is without glochids 

 and has different seeds. The first species was described in 1837, and a second in 1864, 

 both as Of'Hiitia. Weber in 1898 transferred them to Pereskia, proposing a new subgenus 

 for them, but they are much less like Pereskia than Opuntia, for, except as to the seeds, 

 they have little in common with Pcrcskiii; in habit, leaves, spines, flowers, and fruits they 

 are quite unlike any of the pereskias. 



