THE CACTACEAE. 



4. Wilcoxia papillosa sp. nov. 



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

 roots; stems slender with few branches, 3 to 4 dm. long, perhaps longer, 3 to 5 mm. in diameter, 

 glabrous, but the whole surface covered 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 the ovary and 

 flower-tube small, linear-cuspidate, the lower ones naked or nearly so, those at the top of the tube 

 with long white wool and several brown bristles (8 to 12 mm. long) in their axils; perianth-segments 

 2 cm. long; fruit probably spineless. 



Collected by C. A. Purpus at Culiacan, Sinaloa, Mexico, October 1, 1904, and now 

 deposited in the Herbarium of the University of California (No. 160654), and in the same 

 State at Tinamaxtita, San Ignaeio, altitude 1,340 meters, May 20, 1919, by a Mexican 

 Commission which was studying the natural resources of Sinaloa (No. 848). 



The plant is called cardoncillo. 



17. PENIOCEREUS (Berger) Britton and 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, rarely 3 or 6-angled; spines of all the areoles similar; flowers very large for the size 

 of the plant, funnelform, nocturnal, white, the outer perianth-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 as also on the ovary; fruit spiny, ovoid, long-pointed, bright scarlet, fleshy, and 

 edible; seeds black, rugose, with a large oblique hilum. 



A monotypic genus of the southwestern United States and northern Mexico. 



The generic name is from the Greek, signifying thread-cereus. 



1. Peniocereus greggii (Engelmann) Britton and Rose, Contr. U. S. Nat. Herb. 12: 428. 1909. 



Ceretis greggii Engelmann in Wislizenus, Mem. Tour North. Mex. 102. 1848. 

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

 Cereus greggii transmontamis Engelmann, Proc. Amer. Acad. 3: 287. 1856. 

 Cereus greggii cismontanus Engelmann, Proc. Amer. Acad. 3: 287. 1856. 

 Cereus greggii roseiflorus Kunze, Monatsschr. Kakteenk. 20: 172. 1910. 



Root often very large, sometimes 6 dm. in diameter, weighing 60 to 125 pounds, usually 1.5 

 to 20 cm. long by 5 to 8 cm. in diameter; stems 3 dm. 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 re- 

 flexed; filaments erect, exserted; style slender, the stigma- 

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

 including the elongated beak. 



Type locality: Near Chihuahua, Mexico. 

 Distribution: Western Texas, southern New Mexico 

 and Arizona to Sonora, Chihuahua, and Zacatecas. 



Fig. 167. — Flower of Peniocereus greggii. X0.5. 

 Fig. 168. — Fruit of same. X0.5., 



