902 CONTRIBUTIONS FEOM THE NATIONAL HERBARIUM. 



somewhat tuberculate ; spines 10 to 30, yellow to yellowish brown, acicular, 1 

 to 4 cm. long; flowers about 2 cm. long and about as broad when expanded; 

 outer perianth segments obovate, obtuse; Inner perianth segments oblong, 

 about 1 cm. long; fruit globose, densely spiny. 



11. WILCOXIA Britt. & Rose, Contr. U. S. Nat. Herb. 12: 434. 1909. 



Plants usually low and weak, producing a cluster of dahlia-like roots ; stems 

 very slender, more or less branched, the branches often only the diameter of 

 a lead pencil; ribs few and low; spines of all the areoles similar; flowers 

 diurnal, funnelform-campanulate, red or purple, large for the size of the plant, 

 only 1 from an areole, the tube rather short, its areoles bearing spines or 

 bristles and wool; areoles of ovary and fruit bearing spines or bristles and 

 wool ; seeds black, the aril large and basal. 



The following are all the known species. 



Areoles on ovary and flower tube bearing long bristles. 



Stems puberulent 1. W. viperina. 



Stems glabrous. 

 Corolla about 5 cm. long; tube indefinite; seeds dull; spine clusters 3 



to 5 mm. apart 2. W. poselgeri. 



Corolla 10 to 12 cm. long; tube definite; seeds shining; spine clusters 



distant 3. W. striata. 



Areoles on ovary and lower part of flower tube without long bristles. 



4. "W. papillosa. 



1. Wilcoxia viperina (Weber) Britt. &. Rose, Contr. U. S. Nat. Herb. 16: 



242. 1913. 



Cereus viperinus Weber; Goss. Bull. Mus. Hist. Nat. 10: 3S5. 1904. 



Puebla ; type from ZapotitlS,n. 



Stems elongate, branching, the largest ones 1 cm. in diameter, becoming 

 spineless; branches densely velvety-puberulent, 8 mm. in diameter or less; 

 ribs about 8, inconspicuous; spines about 8, appressed, dark, about 5 mm. 

 long; flowers red, 3 cm. long; spines of ovary and corolla tube black, bristle- 

 like, intermixed with long white wool. " Organito de vlbora." 



2. Wilcoxia poselgeri (Lem.) Britt. & Rose, Contr. U. S. Nat. Herb. 12: 



434. 1909. 



Cercns tuherosus Poselger, Allg. Gartenz. 21: 135. 1853. Not C. tuJ)erosus 

 Pfeiff. 1837. 



Echinocereus poselgeri Lem. Cact. 57. 1868. 



Cereus poselgeri Coulter, Contr. U. S. Nat. Herb. 3: 398. 1896. 



Coahuila. Southern Texas. 



Roots tuberous, black, several, near the surface of the ground; stems 60 

 cm. high or less, 6 to 10 mm. thick, with 8 to 10 inconspicuous ribs, the lower 

 and older parts naked, spiny above, the spines almost hiding the ribs; radial 

 spines 9 to 12, appressed, 3 to 5 mm. long, delicate, puberulent; central one 

 ascending, black-tipped, about 1 cm. long, stouter than the radials; flowers 

 purple or pink, 5 cm. long; spines of ovary and flower tube intermixed with 

 white hairs; perianth segments linear, acuminate, about 2.5 cm. long, widely 

 spreading or strongly recurved ; seeds pitted or rugose, 8 mm. long. " Sacasil." 



3. Wilcoxia striata (T. S. Brandeg.) Britt. & Rose, Contr. U. S. Nat. Herb. 



12: 434. 1909. 

 Cereus striatus T. S. Brandeg. Zoe 2: 19. 1891. 

 Cereus diguetii Weber, Bull. Mus. Hist. Nat. 1: 319. 1895. 

 Ba ja California and Sonora ; type from San Jos§ del Cabo, Baja California. 



