io 4 



Tim CACTACEAE. 



13. ERDISIA gen. nov. 



Stems much branched at base, sometimes mainly subterranean, the branches slender, erect, 

 ling, or pendent; ribs few, crenate, with spiny areolcs; flowers small, funnelform-campanulate, 

 the tube short; throat short, funnelform, covered with stamens; outer perianth-segments obtuse 

 or sometimes with acute tips; filaments numerous, white, about half the length of the inner 

 perianth-segments; style stout, a half longer than the stamens; ovary tuberculate, bearing minute 

 ovate scales with spines and felt in their axils; fruit juicy, small, globular, bearing clusters of deciduous 

 spines; seeds numerous, minute. 



The genus consists of 4 species, so far as known; Cereus squarrosus Vaupel is the 

 type species. It is named in honor of EHwood C. Erdis, who was in charge of the topo- 

 graphical wrwt of the Yale University Peruvian Expedition, 1914. 



The plants resemble in habit some of the bushy Cuban species of the genus Leptoccrciis. 

 In the shape of the flowers, the spiny ovary, and the deciduous spines on the fruit, some 

 of them suggest Echinoccrcus, but the habit is very different, and no Echinoccrcus is known 

 to be of South American origin. 



KEY TO SPECIES. 



Stem and branches cylindric. 



Flowers bright red or scarlet; inner series of stamens not united i. E. squnrrasa 



Flowers yellow; inner series of stamens united into a tube . .2. . philippii 



Branches clavate; stem more or less subterranean. 



Flowers yellow . . . 3. E. meyciiii 



Flowers purple . . .4. E. spin (flora 



1. Erdisia squarrosa (Vaupel). 



Cereus squarrosus Vaupel, Bot. Jahrb. Engler 50: Beibl. in: 21. 1913. 



Stems i to 2 meters long, i to 3 cm. in diameter; ribs 8 or 9; areoles i to 1.5 cm. apart; spines 

 about 15, yellowish, very unequal, somewhat swollen at base, the longest ones 4 cm. long; flowers 

 borne towar^the ends of branches, 2.5 to 4 cm. long including the ovary, sometimes as much as 5 

 cm. broad; inner perianth-segments 1.5 cm. long; filaments i cm. long or less; style stout, 1.5 cm. 

 long; fruit 1.5 to 2 cm. in diameter, juicy, spiny, the clusters of spines falling off early; seeds minute. 



I'IG. 154. Erdisia squarrosa. 



Type 



: Tarma, Department of Junin, Peru. 

 The highlands of eastern Peru. 

 This species was collected by Dr. J. N. Rose below Cuzco, Peru, in 1914, when flowers 

 and stems were obtained. Some of the living plants which were sent to the New York 



