WII.O >XI.\. 



Herbarium of the Museum of Paris, where it was examined by Dr. Rose in 1912. It is 

 the same as C. A. Purpus's No. 3301 collected at the type locality in 1908 and distributed 

 in his sets of specimens. It is called in Mexico organito de vibora. 



The plant is remarkable among Ccrccac in having puberulent stems. We include it in 

 Wilcoxia, but are uninformed as to the characters of the roots, which are tuberous in the 

 other species. 



Figure 163 shows pieces of the stem, from an herbarium specimen collected by C. A. 

 Purpus at the type locality. 



2. Wilcoxia poselgeri (Lemairc) Britton and Rose, Contr. U. S. Nat. Herb. 12: 434. 1909. 



Cereus tuberosits Poselger, Allg. Gartenz. 21: 135. 1853. Not PfcifTer, 1837. 

 Echinocereus poselgeri Lemairc, Cact. 57. 1868. 



Echinocereus tuberosus Riimpler in Fdrster, Handb. Cact. ed. 2. 783. 1885. 

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



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 em. 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; style pale green; 

 stigma-lobes slender, green; seeds pitted or rugose, 8 mm. long. 



Type locality: Texas. 



Distribution: Southern Texas and Coahuila. 



This cactus does not grow well on its own roots in green- 

 house cultivation, but gradually loses its vitality; we have had 

 plants, however, to persist in cultivation for ten years. If 

 grafted on cuttings of Selenicereus pteranthus, very vigorous 

 plants can be developed, which will flower each year. It is 

 sometimes called sacasil. 



The flowers open in the afternoon, but close at night, 

 opening and closing in this way for from 5 to 9 days. They 

 have a pleasing odor. 



Illustrations: Monatsschr. Kakteenk. 13: 77; Knippel, 

 Kakteen pi. 15; Bliihende Kakteen 1: pi. 38; Schelle, Handb. 

 Kakteenk. f. 53, as Echinocereus tuberosus; Engelmann, Cact. 

 Mex. Bound, pi. 59, f. 12; Goebel, Pflanz. Schild. 1: pi. 4, f. 1 ; 

 Blanc, Cacti 38. f. 348, 349, as C. tuberosus. 



Figure 1 64 is from a photograph of a flowering plant in the 

 collection of the New York Botanical Garden; figure 165 shows 

 the cluster of tuberous roots of a plant grown at Floral Park, New York, in 1890. 



Fig. 165. — Cluster of tuberous 

 roots of W. poselgeri. X0.6. 



3. Wilcoxia striata (Brandegee) Britton and Rose, Contr. U. S. Nat. Herb. 12: 434. 1909. 



Cereus slriatus Brandegee, Zoe 2:19. 1891. 



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



Roots brownish, deep-seated ; stem vine-like, very slender, usually with 9 indistinct ribs, grayish ; 

 spines about 9, 1.5 to 3 mm. long, acicular, weak, appressed, 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. 



Type locality: San Jose del Cabo, Lower California. 



Distribution: Lower California and Sonora, Mexico. 



The natives call it pitayita, pitahayita, sacamatraca, saramatraca, and jaramataca. 



This differs from the type species of the genus in its much larger, funnelform flowers. 



