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 1917 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. Echinocactns 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 yellow, 
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 cm. long, dehiscing by 
FIG. 191.—Echinocactus polycephalus. a basal pore, seeds angled, papillose, dull black, 3 to 4 
the seed: * mm. long; hilum large, lateral but below the middle of 
1e 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). 
iustrations: Pac. R. Rep. 4: pl. 3, f. 4 to 6; Dict. Gard. Nicholson 4: 540. f. 22; Suppl. 
335. ; 358; Forster, Handb. Cact. ed. 2. 204. f. 13: Goebel, Pflanz. Schild. 1: f. 12, 43; 
Meehan, Native Fl. Ferns U. S. 2: pl. 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. 
