HICKENIA. 
207 
“Echinocactus sp. 
“Prov. Jujuy; among rocks at Moreno, 3,500 m. alt. 
“Very similar in habit to Echinocactus nidus Sohrens, as shown in Monatsschr. Kakteenk. 10: 
122; since, however, no description of that species is furnished, I can not tell whether or not these are 
identical. 
“Spherical, 3 to 4 dm. high; ribs running spirally, divided into well-marked tubercles; areoles 
oval, covered with wool; radial spines and central spines little differentiated, all together 20 to 25, 
up to 45 cm. long, the outer ones more or less pressed on the plant-body, forming an extraordinarily 
thick network; the summit is naked, the spines closing in over it; the finer spines are white, the 
stouter ones golden-yellow at the base, lilac-colored in the middle, violet at the tips; the flowers 
appear about 2 cm. from the growing-point; they are yellowish green, 3.5 to 4 cm. long.” (Fries, 
Nov. Act. Reg. Soc. Upsal. IV. 1: 121, 122. 1905.) 
24. HICKENIA gen. nov. 
Small, usually globular, very spiny cacti; ribs more or less definite, sometimes spiraled, divided 
into low, rounded tubercles; spines radial and central, one of the latter strongly hooked; flowers 
central, large for the size of the plant, borne at the top of the very young tubercles, subcampanu- 
late, with a broad spreading limb; scales on ovary and flower-tube small, their axils filled with wool 
and bristles; fruit small, oblong, thin-walled, many-seeded; seeds minute, brown, shining, smooth, 
with a prominent white corky hilum. 
Figs. 220 and 221.—Hickenia microsperma. 
Type species: Echinocactus microspermus Weber. 
The genus is named for Dr. C. Hicken, professor in the University of Buenos Aires. 
Only one species is here recognized, a native of Argentina, but we find such great 
diversity in the spines, arrangement of the tubercles, and the color and size of the flowers 
that we suspect that more material would lead to some segregations. 
1. Hickenia microsperma (Weber). 
Echinocactus microspermus Weber, Diet. Hort. Bois 469. 1896. 
Echinocactus microspermus macrancistrus Schumann, Monatsschr. Kakteenk. 12: 157. 1902. 
Simple or in small clusters, usually globular, sometimes short-cylindric and 2 dm. high, 5 to 10 
cm. in diameter, the surface divided into low tubercles; tubercles arranged in definite straight or 
spiraled ribs or very indefinitely arranged; radial spines 11 to 25, white, acicular, spreading, 4 to 6 mm. 
long; central spines 3 or 4, red to brown, subulate, glabrous or pubescent, the lowest one hooked at 
apex, ascending, spreading, or reflexed; flowers variable in color, bright yellow to red, 2 to 4 cm. 
broad; filaments red; style and stigma-lobes light reddish yellow; seeds 0.5 mm. long. 
Type locality: Tucuman, Argentina. 
Distribution: Northern Argentina. 
