STANDLEY TREES AND SHRUBS OF MEXICO. 903 



Roots brown, shallow-seated; stem vinelike, very slender, usually with 9 

 indistinct ribs, grayish ; spines about 9, 1.5 to 3 mm. long, acicular, weak, ap- 

 pressed, brownish, the areoles rather distant ; flowers 10 to 12 cm. long, purple, 

 the areoles bearing slender bristle-like spines and long wool; fruit pyriform, 

 3 to 4 cm. long, scarlet, spiny, the spines deciduous; seeds minutely pitted. 

 " Pitahayita," " sacamatraca," " saramatraca," " jarramatraca," " racamatraca.' 



A cloth saturated with the juice of the crushed roots is sometimes applied 

 to the chest to relieve inflammation of the lungs. 



4. Wilcoxia papillosa Britt. & Rose, Cactaceae 2: 112. 1920. 



Sinaloa, the type from Culiacan. 



Tap-root spindle-shaped, fleshy, 4 to 7 cm. long, 2 cm. in diameter, giving 

 ofE long fibrous roots; stems slender, with few branches, 30 to 40 cm. long, 

 perhaps longer, 3 to 5 mm. in diameter, glabrous, but the whole surface cov- 

 ered with minute papillae; ribs low, indistinct, perhaps 3 to 5 ; areoles small, 

 distant, 1 to 3 cm long, white- woolly ; spines in clusters of 6 to 8, minute, 

 yellowish brown, bulbose at base, 1 to 3 mm. long; flowers scarlet, 4 to 5 cm. 

 long; scales on ovary and flower tube small, linear-cuspidate, those at the top 

 of the tube with long white wool and several brown bristles in their axils; 

 perianth segments 2 cm. long. "Cardoncillo." 



12. PENIOCEREUS Britt. & Rose, Contr. U. S. Nat. Herb. 12: 428. 1909. 



Plants low, slender, from an enormous fleshy turnip-shaped root ; stems 

 and branches usually 4 or 5-angled ; spines of all the areoles similar ; flowers 

 very large, funnelform, nocturnal, white, the outer segments tinged with red; 

 tube of flower long, slender, with long hairs in the axils of the upper scales, 

 but with clusters of spines on the lower part and also on the ovary; fruit 

 spiny, ovoid, long-pointed, bright red, fleshy ; seeds black, rugose. 



The genus consists of two species. 



Young growth pubescent ; seeds dull black 1. P. greggii. 



Young growth glabrous ; seeds shining 2. P. johnstonii. 



1. Peniocereus greggii (Engelm.) Britt. & Rose, Contr. U. S. Nat. Herb. 12: 



428. 1909. 



Cereus greggii Engelm. in Wisliz. Mem. North. Mex. 102. 1848. 



Cereus pottsii Salm-Dj'ck, Cact. Hort. Dyck. 1849. 208. 1850. 



Sonora, Chihuahua, and Zacatecas; type collected near the city of Chihua- 

 hua. Western Texas to Arizona. 



Root often very large, sometimes 60 cm. in diameter, weighing GO to 125 

 pounds, usually 15 to 20 cm. long by 5 to 8 cm. in diameter ; stems 30 cm. to 

 3 meters high, 2 to 2.5 cm. in diameter, the young parts pubescent ; spines 

 small, blackish ; radials 6 to 9"; central usually 1, sometimes 2 ; flower 15 to 

 20 cm. long, the tube slender and terminating in a short funnelform throat, 

 covered with stamens; inner perianth segments lanceolate, acute, 4 cm. long, 

 spreading, or the outer ones reflexed ; filaments erect, exserted ; style slender, 

 the stigma lobes about 1 cm. long; fruit tuberculate, 12 to 15 cm. long, including 

 the elongate beak. " Huevo de venado " (Patoni). 



2. Peniocereus johnstonii Britt. & Rose, Journ. Washington Acad. Sci. 12: 329. 



f. 2. 1922. 



Baja California, the type from San Josef Island. 



Plant climbing or clambering, up to 3 meters long; stems and branches 3 

 to 5-angled ; spines 9 to 12, brown to black ; upper radial spines short, stubby, 

 swollen at base, nearly black, the two lower light brown, elongate, bristle-like 



