860 CONTRIBUTIONS FROM THE NATIONAL, HERBAKIUM. 



2. PERESKIOPSIS Britt. & Rose, Smiths. Misc. Coll. 50: 331. 1907. 



Trees and shrubs, in habit and foliage similar to Pereskia; old trunk form- 

 ing a solid woody cylinder covered with bark and resembling the ordinary 

 dicotyledonous stem ; areoles circular, spine-bearing or sometimes spineless, 

 also bearing hairs, wool, and usually glochids ; flowers similar to those of 

 Opuntia; ovary sessile (one species described as pedunculate), with leaves at 

 the areoles (except in one species) ; fruit red; seeds bony, few, covered with 

 matted hairs. 



Seems, ovary, and often the leaves more or less pubescent. 

 Normal leaves long-acuminate, narrow, with narrow cuneate base. 



1. P. velutina. 



Normal leaves abruptly pointed, somewhat cuneate at base 2. P. diguetii. 



Stems, ovary, and leaves glabrous. 



Leaves, at least some of them, not much longer than broad. 



Fruit without leaves 3. P. opuntiaeflora. 



Fruit with leaves subtending the areoles. 

 Areoles white, with few or no glochids. 



Leaves orbicular or nearly so, rounded or apiculate at apex. 



4. P. rotundifolia. 

 Leaves, at least the upper ones, obovate or elliptic, acute at both ends. 



5. P. chapistle. 



Areoles dark, filled with numerous brown glochids 6. P. porteri. 



Leaves, at least some of them, twice as long as broad or longer. 



Leaves spatulate 7. P. spathulata. 



Leaves elliptic to oblong or obovate. 



Leaves pale green, glaucous 8. P. pititache. 



Leaves bright green, shining 9. P. aquosa. 



1. Pereskiopsis velutina Rose, Smiths. Misc. Coll. 50 : 333. 1907. 

 Central Mexico, the type from Quer6taro. 



Stems weak and spreading, forming compact bushes 1 meter high or more; 

 old stems with cherry-brown bark ; young branches green, borne nearly at right 

 angles to the old stem, velvety-pubescent ; areoles bearing long white hairs, 

 several short spines, and some glochids; leaves elliptic to ovate-elliptic, 2 to 

 6 cm. long by 1.5 to 2.5 cm. broad, acuminate, or acute at both ends, dull green, 

 more or less velvety-puberulent on both surfaces; flowers sessile on the sec- 

 ond-year branches ; ovary obovoid to oblong, pubescent, bearing large leaves 

 and areoles similar to those of the stem ; leaves on ovary spreading or ascend- 

 ing and persisting after the flower falls ; sepals green or deep and tinged with 

 yellow ; petals bright yellow. " Nopaleta," " cola de diablo." 



The plant is grown in hedges about Queretaro. 



2. Pereskiopsis diguetii (Weber) Britt. & Rose, Smiths. Misc. Coll. 50: 332. 



1907. 



Opuntia diguetii Weber, Bull. Mus. Hist. Nat. 4: 166. 1898. 



Jalisco to Oaxaca ; type collected near Guadalajara, Jalisco. 



Tall shrub, larger than the preceding species ; old stems reddish ; branches 

 pubescent ; areoles when young filled with long cobwebby hairs, when old 

 large and filled with short black wool; leaves elliptic to obovate, 3 to 5 cm. 

 long, usually abruptly pointed, more or less cuneate at base ; spines usually 1, 

 rarely as many as 4, at first nearly black, in time becoming lighter, sometimes 

 nearly 7 cm. long; glochids brownish, not very abundant; flowers yellow; 

 fruit 3 cm. long, red, pubescent, its areoles often bearing spines as well as 

 glochids; seeds white, 5 mm. broad, covered with matted hairs. "Tasajillo," 

 " alf ilerillo " (Jalisco). 



