V 



ILLUSTRATED STUDIES IN THE GENUS OPUNTIA.— I 



BY DAVID GRIFFITHS. 



This paper contains descriptions of species collected and 

 studied by myself in the field during the past five years. The 

 type locality of each has been visited not less than twice, 

 many of the plants have been grown to maturity from cut- 

 tings, and seedlings are being cultivated. The type numbers 

 refer to specimens mounted on sheets, but the plants are also 

 in cultivation. 



The studies are to be continued as plants reach maturity. 

 It will doubtless be necessary to say more about some of these 

 as they get older and present other diagnostic characters. 



Opuntia Cardenche sp. nov. 



An open branching tree, 1.5 to 2.5 meters high, with a dark scaly trunk 



m 



6 to 10 cm. in diameter; joints variable, laterals commonly easily separable 

 and shorter (1 dm.) than the main or secondary axes, which may vary 

 from 2 to 6 dm. in length, last year's joints commonly close to 2 cm. 

 in diameter, tuberculate, with the large oval areola on the upper shorter 

 slope of the long compressed tubercle, the upper tubercular slope being 

 nearly perpendicular in young joints; areoles broadly ovate, 5 to 7 mm. 

 in longest diameter, usually showing distinct subareolate areas, gray-bluck 

 below and gray-brown above, the wool area developing for some years until 

 the areole becomes subcircular, often 1 cm. in diameter, or often elongated 

 transversely; spicules in a compact tuft in upper portion of areole, dirty 

 gray or yellowish in situ but distinctly bright reddish brown when separated 

 from plant; spines on last year's joints 1 to 4, mostly 4, and most numer- 

 ous near middle of joint, bone-like, translucent, or slightly flesh colored, 

 or even reddish tinged at very base, erect, spreading, with lower central 

 one longest (2.5 cm.) and others slightly shorter, all with deep straw-colored 

 medium loose sheaths; intermixed with spines but distinct from spicules 

 are 4 to 6 very small unsheathed, inconspicuous, fugacious, gray-black 

 bristles, 3 to 6 mm. long; flowers light purple, about 4 cm. in diameter; 

 petals obovate to obcordate, cuspidate pointed, denticulate, and often 

 slightly crenulate; sepals greenish (second row), short, abruptly cuspidate 

 pointed; filaments purphsh green, stout; style white at base and tinged 

 with purple above; stigma yellowish white, about 6-parted; ovary obo- 

 vate, deeply pitted at apex, 2.5 cm. long, with areoles subcircular, 2 to 3 

 mm. in diameter on upper short and almost vertical slope of tubercle, 

 bearing a compact tuft of spicules, a few scattering bristles like those of the 

 stem, and a few fugacious, delicate white or yellowish, partially sheathed 



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