104 



THE CACTACEAE. 



13. ERDISIA gen. nov. 



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

 ascending, or pendent; ribs few, crenate, with spiny areoles; 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 Ellwood C. Erdis, who was in charge of the topo- 

 graphical work of the Yale University Peruvian Expedition, 19 14. 



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

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

 of them suggest Echinocereus, but the habit is very different, and no Echinocereus 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 z. E. squarrosa 



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



Branches clavate; stem more or less subterranean. 



Flowers yellow , 3. E. meyenii 



Flowers purple 4. E. spiniflora 



1. Erdisia squarrosa (Vaupel). 



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

 Stems 1 to 2 meters long, 1 to 3 cm. in diameter; ribs 8 or 9; areoles 1 to 1.5 cm. apart; spines 

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

 borne toward 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 1 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. 



Fig. 154. — Erdisia squarrosa. 



Type locality: Tarma, Department of Junin, Peru. 

 Distribution: 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 



