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rERESKiorsis. 



25 



PERESKIOPSIS 



1 . 1 907 



Trees and shrubs, in habit and foUage similar to Pcrcskia; old trunk forming a solid woody 

 cylmder covered with bark and resembling the ordinary dicotyledonous stem; areoles circular, 

 spine-beanng or sometimes spineless, also bearing hairs, wool, and usually glochids; flowers similar 

 to those of Opunha; ovary sessile (one species described as pedunculate), with leaves at the areoks 



Type species : Opuntia hrandcscei Schu 



common in heds^es and thickets of Mexico 



number 



have been described. In our first discussion of the genus {op. cit.) we recognized 



II 



were described, as early as 



from descriptions. There now seem to be at least 



Washington and New York. Two of the plants 



:ies of Pcreskia, and here they remained with 2 



Weber transferred them to Op 



them in a new subgenus, Percskiopuntia. The same year Dr. Karl Schumann adopted 

 Weber's conclusions, publishing his treatment of the subgenus and assigning 5 species to it. 



In its large leaves and woody, spiny stems, this group suggests Pcrcskia, but it has 

 glochids and different flowers, fruit, and seeds; in flowers, fruit, 

 sembles Opuntia, but on account of habit and fohage must be excluded from that genus. 



In view of these differences, Britton and Rose in 1907 estabhshed the genus Peres - 

 kiopsis and listed 1 1 species, 4 of which had been originally described as species of Pereskia 



seeds 



Op 



most 



the pereskias and opuntias so as to compare them. Unfortunately we are not able to 

 describe all the species fully, for they have never been known to flower in cultivation, 



some of the species, at least, bloom 



sometimes 



The leaves on the 



and in greenhouse cultivation the leaves of some species are narrower than when the plants 



growing 



name is from the Greek and sijrnifies resemblincr Pcrcsk 



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Key to Species, 



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



Normal leaves long-acuminate, narrow, with narrow cuneate bases i. P. veJutina 



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



Stems, ovary, and leaves glabrous. 



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



Fruit without leaves, at least so figured 3. P, opunliaejlora 



Fruit with leaves subtending the areoles. 

 Areoles white, with few glochids or none. 



Leaves orbicular or nearly so, rounded or apiculate 4. P. rotundifolia 



Leaves, at least the upper ones, obovate or elliptic, acute at both ends 5- /'. 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- spatliulaia 



Leaves elliptic to oblong, or obovate. 



Leaves pale green, glaucous 8. P. pititache 



Leaves bright gr.en, shining. 



Glochids few, yellow 9' P- (iqnosa 



Glochids many, brown 10. /*. kdlcrmanii 



1. Pereskiopsis velutina Rose, Smiths. Misc. Coll. 50: 2>7,:S' 1907- 



Stems weak and spreading, forming compact bushes 9 to 12 dm. high or sometimes higher; 

 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 and several short spines and some glochids; 

 leaves elHptic 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, when very young brighter green; 

 flowers sessile on the second-year branches; ovary obovoid to oblong, pubescent, bearing large 



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