SCEEROCACTUS. 213 



1. Sclerocactus whipplei (Engelmann and Bigelow). 



Echinocactus whipplei Engelmann and Bigelow in Engelmann, Proc. Amer. Acad. 3: 271. 1856. 

 Echinocactus whipplei spinosior Engelmann, Trans. St. Louis Acad. 2: 199. 1863. 



Usually single, but sometimes in small clusters, globose, 7.5 cm. in diameter or oblong and up to 

 15 cm. long; ribs 13 to 15, often spiraled, prominent, more or less tubercled; spines on seedlings all 

 radials but on old plants both radials and centrals; radial spines 7 to 11, somewhat flattened, spread- 

 ing or recurved, 12 to 18 mm. long, mostly white, but some black; central spines usually 4, the upper- 

 most one flattened and straight, all or only one of the 3 lower ones hooked, usually brown or black, 

 stouter than the radials ; flowers from near the center of the plant, often abundant, short-campanu- 

 late, purplish to rose-colored, 3 to 4 cm. long; outer perianth -segments green with pale margins, 

 broad, obtuse or acute ; inner perianth-segments lavender, oblong, acuminate ; tube-proper very short ; 

 filaments lavender; style reddish, puberulent throughout; fruit oblong, 1.5 cm. long, red, nearly 

 naked; scales on the fruit small, hyaline, each bearing in its axil a small tuft of hair; seeds 3 to 3.4 

 mm. long, much larger at the upper end than at the lower; hilum large, lateral on the lower half of 

 the seed; "embryo curved, about three-fourths around a rather copious albumen." 



Type locality: On the Little Colorado in Arizona. 



Distribution: Northern Arizona, southeastern Utah, and western Colorado. 



According to Mr. M. E. Jones who knows this species very well it is found only on the 

 high mesas growing in clayey soil. It is an inconspicuous plant usually found singly under 

 small bushes and is easily overlooked except when in flower. The species has a wide range 

 and shows considerable variation in number, color, and shape of spines, but we are not dis- 

 posed to recognize the variety spinosior which seems to grade into the type. 



This cactus is remarkable in having a puberulent style and is the only one we recall 

 of the many species of cacti examined in which the style is puberulent throughout. 



E. whipplei nanus (Monatsschr. Kakteenk. 10: 119. 1900) we do not know; it is doubt- 

 less only a form. 



Echinocactus glaucus Schumann (Gesamtb. Kakteen 438. 1898), of which E. subglancus 

 Rydberg (Fl. Rocky Mountains 580. 191 7) is a change of name, based on Purpus's plant 

 from Dry Creek, Mesa Grande, Colorado, probably belongs here, although we have not seen 

 the type specimen. Here we would refer specimens so named by Standley from north- 

 western Arizona. 



Echinocactus pubispinus Engelmann (Trans. St. Louis Acad. 2: 199. 1863), which came 

 from Pleasant Valley near Salt Lake Desert, is known only from the type which was without 

 flowers or fruit. It is certainly related to this species if not identical with it. It is described 

 as having pubescent spines, a character also possessed by E. whipplei in the early stages of 

 its growth. 



Echinocactus spinosior Brandegee, referred to by Purpus (Monatsschr. Kakteenk. 10: 

 97. 1900), although never published, doubtless refers to the variety of this species with the 

 same name. 



Illustrations: Pac. R. Rep. 4: pi. 1; Cact. Journ. 1: pi. V, in part; Stand. Cycl. Hort. 

 Bailey 2: f. 1371; Mollers Deutsche Gart. Zeit. 25: 474. f. 6, No. 2; Meehans' Monthly 9: 

 pi. 3, as Echinocactus whipplei; Gartenwelt 1: 89, as Echinocactus glaucus. 



Plate xvi, figure 2, shows the plant collected by Dr. P. A. Rydberg in 191 1 at Moab, 

 Utah, which flowered in the New York Botanical Garden in April 1912. 



2. Sclerocactus polyancistrus (Engelmann and Bigelow). 



Echinocactus polyancistrus Engelmann and Bigelow in Engelmann, Proc. Amer. Acad. 3: 272. 1856. 



Simple, globular to oblong, 1 to 4 dm. high; ribs 13 to 17, 1 to 1.5 cm. high, obtuse, strongly 

 undulate; areoles 1 to 1.5 cm. apart; spines about 20; radial spines acicular, white, 1 to 2.5 cm. long; 

 central spines several, rather unequal, up to 12.5 cm. long, the upper ones erect, white, flattened, the 

 others brown, spreading, terete and often hooked; flowers magenta-colored, nearly 8 cm. long, and 

 perhaps as broad; inner perianth-segments oblong, about 4 cm. long; throat of flower broad, 



