174 



THE CACTACEAE. 



Type locality: Kanab Plateau on the borders of Utah and Arizona. 



Distribution: Extreme southwestern Utah and northern Arizona. 



According to Dr. Coulter, this plant was given a specific name by Dr. Engelmann, but 

 was never published by him. In 191 7 Dr. Rydberg recognized it as a good species and used 

 Engelmann's binomial for the first time. Through the kindness of Dr. J. M. Greenman, 

 we have been able to study the material of Siler, now in the herbarium of the Missouri 

 Botanical Garden, upon which this species is based. The material consists of two herba- 

 rium sheets as follows: No. 106799, without data, contains a single flower; No. 106798 

 contains two collections, one obtained in 1882 and the other in November 1881. These 

 two collections show a cluster of spines, some scales from the ovary, and a quantity of seeds. 

 Siler's plant from Kanab Mountains, referred to by Coulter, is missing. Dr. Coulter 

 treated this plant as a variety of Echinocactus polycephalus and referred to it several other 

 collections including Rusby's No. 2902 from Peach Springs, Arizona, which we have also 

 studied. 



In September 1920 James H. Ferriss sent us a fruit from a living plant collected by Mr. 

 Willard N. Clute on the Painted Desert in northern Arizona which we identified as the same 

 as Rusby's plant and now know to be the same as Siler's plant. We at once saw that the 

 seeds were very different from those of E. polycephalus and this led to a restudy of our 

 herbarium specimens which divided very definitely into the two species with good spine, 

 flower, fruit, and seed characters. 



Figure 190 is from a photograph made by T. Ashby Flynn, photographer in the U. S. 

 National Museum, of the plant collected by Mr. Clute, referred to above 



8. Echinocactus polycephalus Engelmann and Bigelow in Engelmann, Proc. Amer. Acad. 3:276. 



1856. 



Echinocactus polycephalus flavispinus Haage jr., Monatsschr. Kakteenk. 9: 43. 1899. 



Solitary when young, in age forming large clumps of 20 to 30 heads, each globular to short- 

 cylindric, sometimes as much as 7 dm. high but usually smaller; ribs 13 to 21, rather stout, 2 to 3 cm. 

 high, somewhat undulate, nearly hidden under the dense spine-armament; areoles large, 10 to 12 mm. 



in diameter, 1 to 3.5 cm. apart; spines 7 to 15, when 

 young covered with a downy felt but afterwards glabrate, 

 reddish, subulate, more or less flattened, the radials 2.5 

 to 5 cm. long; central spines 4, stouter than the radials, 

 3 to 9 cm. long, more or less annulate; flowers vellow, 

 5 to 6 cm. long; scales on the ovary minute, hidden under 

 the mass of long wool borne in their axils; scales on the 

 flower-tube numerous, only a little longer than the wool, 

 chartaceous, pungent; inner perianth-segments linear- 

 oblong, 2.5 to 3 cm. long, entire, obtuse (see Meehan's 

 plate); style slender, about 3 cm. long; fruit densely 

 woolly, crowned by the somewhat spinescent scales, 

 globose to oblong, dry, 1.5 to 2.5 em. long, dehiscing by 

 ,, ^ , . . , , a basal pore; seeds angled, papillose, dull black, 3 to 4 



mm. long; hilum large, lateral but below the middle of 

 the seed; "embryo curved, the cotyledons buried in the large albumen." (Engelmann.) 



Type locality: On the Mojave River, California. 



Distribution: Nevada, Utah, western Arizona, southern California to northern Sonora; 

 reported from Lower California (Meehan, Rost). 



Illustrations: Pac. R. Rep. 4: pi. 3, f. 4 to 6; Diet. Gard. Nicholson 4: 540. f. 22 ; Suppl. 

 335- r - 358; Forster, Handb. Cact. ed. 2. 204. f. 13: Goebel, Pflanz. Schild. 1: f. 12, 43; 

 Meehan, Native Fl. Ferns U. S. 2: pi. 33; Monatsschr. Kakteenk. 16: 107; Schelle, Handb. 

 Kakteenk. 163. f. 93; Watson, Cact. Cult. 115. f. 42. 



Figure 191 is from a photograph taken by Dr. MacDougal near Barstow, California. 



