no 



THH CACTACEAE. 



This plant was collected for Cereus melanurus, but it is too tall and stout and has 

 diflerciit spines and smaller flowers. We have living specimens of this plant collected by 

 Scfior Porto, but they have not yet flowered in cultivation. 



16. WILCOXIA Britton and 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 i from an areole, the tube rather short, its areoles bearing spines or bristles and wool; 



and 



poselgeri Lemaire, 

 Mexico, compose 



very 



genus, while the second and third species have been considered as belonging to Cereus 



proper 



has been an enthusiastic student of plants. 



Timothy E. Wilcox, U. S. A., who for many 



Khy to Species. 



Areoles on ovary and flower-tube bearing long bristles. 



Stems puberulent ■. 



Stems glabrous. 



I. W. viperina 



Corolla about 5 cm. long; tube indefinite; seeds dull; spine-clusters approximate, 3 to 5 mm 

 Corolla 10 to 12 cm. long; tube definite; seeds shining; spine-clusters distant, 7 to 15 mm 



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



1. Wilcoxia viperina (Weber) Britton 



and Rose, Contr. U. S, Nat. Herb. 

 16: 242. 1913. 



Cereus viperinns Weber in Gosselin, Bull. 

 Mus. Hist. Nat. Paris 10: 385. 1904. 



Stems elongated, branching, the 

 largest ones seen i cm. in diameter and 

 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, about 3 cm. 

 long; spines of ovary and corolla- tube 

 black, bristle-like, intermixed with long 

 white wool. 



apart. .2. W. poselgeri 

 apart. .3. W. striata 

 4. W. papulosa 



Fig. 163. — Sections of stem of W. 



viperina. X 0.8 



Type locality: Zapotitlan, Mexico. 



Southern Puebla, 



Distribution: 

 Mexico. 



The type of this species was col- 

 lected by L. Diguet and is now in the 



t r 



1 



Fig. 164.— Wilcoxia poselgeri 



\ 



