ILLUSTRATED STUDIES IN THE GENUS OPUNTIA — III. 169 



1 



acterizations, modified by several miscellaneous notes from 

 various localities, one -description having been written in 



the type locality and the other drawn from a three year old 

 seedling. The type specimen is No. 8141 D. G., collected 

 near Zacatecas, Mexico, September 19, 1905. — Plate 22, upper 

 figure. 



» 



Opiintia lubrica sp. nov. 



A low ascending, spreading species very similar in habit to O. micro- 

 dasys, frequently 4£ dm. high and when well developed 10 dm. or 

 more in diameter; joints sub-circular to obovate, about 15 by 20 cm. , 

 or in case of last joints of previous year about 12 by 15 cm., bright, 

 glossy, leaf-green, very evidently papillate but scarcely pubescent 

 under a lens; leaves subulate, cuspidate-pointed, 6 to 9 mm. in length; 

 areoles 15 to 22 mm. apart, 4 to 6 mm in diameter, sub-circular, prom- 

 inent; spicules prominent, 4 to 5 mm. in length, erect, bushy, in cres- 

 centic tufts in upper portion of areoles, becoming much more numerous 

 in age, and at 2 to 4 years completely filling the areole, and, like O. 

 rufida and some other species, becoming very abundant and conspicu- 

 ous by proliferation of areolar tissue into short raised or columnar 

 structures; spines exceedingly variable, sometimes [nearly absent, 

 again quite abundant and irregularly distributed, none too many, 

 mostly 1 to 3, becoming more numerous with age and in scattering 

 areoles to as high as 16, mostly about 12 mm. long, but sometimes 2J 

 cm., yellowish, translucent, bonelike, sometimes darker at base; fruits 

 decidedly acid, light red without with yellowish green rind and red 

 pulp; seed small, thin shelled, about 3 mm. in diameter. 



The habit of this species resembles that of 0. microdasys, 

 but it is a more robust plant with heavier glossy joints 

 smooth to the touch and with color of entirely different 



character. 



. The description is a compilation of partial descriptions 

 made in the type locality and notes upon cultivated, nearly 

 mature plants. The type is No. 8439 D. G., collected near 

 Alonzo, Mexico, August 23, 1906, backed up by several 

 specimens put up from cultivated material. The cultivated 

 plants have not yet bloomed, although one of them is now 

 in the third year's growth from a single joint cutting, 



Plate 23. 



Opiintia nigrita sp. nov. 



An erect, open-branching, stout, arborescent plant with distinct 

 cylindrical trunk and spread of branch about like O. pachona, com- 







