STANDLEY TREES AND SHRUBS OF MEXICO. 907 



Cereus princeps Pfeiff. Enum. Cact. 108. 1837. 



Cereus ramosus Karw. ; Pfeiff. Enum. Cact. 108. 1837. 



Cereus Mxaniensis Karw. ; Pfeiff. Enum. Cact. 109. 1837. 



Cereals nitidus Salm-Dycli, Cact. Hort. Dycls. 1849. 211. 1850. 



Cereus sirul Weber; Goss. Bull. Mus. Hist. Nat. 10: 384. 1904. 



Eastern coast of Mexico. Texas, Central America, northern Soutli America, 

 and Guadeloupe. 



Stem clambering, usually 2 to 3 or sometimes 7 meters high, but when 

 growing in the open more or less arched and rooting at the tip, then making 

 other arches and thus forming large colonies; old trunk becoming nearly 

 round, 5 cm. in diameter or more ; joints 3 to 8 cm. broad, 3 to o-angled, low- 

 crenate ; juvenile growth nearly terete, with (> to 8 low ribs, approximate are- 

 oles, and numerous short acicular spines ; areoles on normal branches 3 to 5 

 cm. apart ; spines acicular or gray, subulate ; radials at first 6 or 7, 1 to 4 cm. 

 long; central spine often solitary, longer than the radials; spines of old are- 

 oles often as many as 12, of which several are centrals ; flowers 14 to 20 cm. 

 long; tube and ovary bearing conspicuous areoles with brown felt and sev- 

 eral subulate spines ; outer perianth segments green ; inner perianth segments 

 white, acuminate ; fruit oblong, red, edible ; cotyledons broadly ovate, 5 to 8 

 mm. long, thick, united at base, gradually passing below into the spindle- 

 shaped hypocotyl. " Pitahaya," " pitahaya naranjada," " pitahaya morada." * 



3. Acanthocereus subinermis Britt. & Rose, Cactaceae 2: 125. 1920. 

 Type collected between Mitla and Oaxaca, State of Oaxaca. 



Plants 1 meter high or higher ; joints stout, 5 to 7 cm. broad, strongly 3 

 or 4-angled, bright green, somewhat shining, usually short ; areoles 3 to 4 cm. 

 apart ; spines either wanting or short, when present 6 to 10 at an areole, acicu- 

 lar, usually less than 1.5 cm. long; flowers 15 to 22 cm. long; outer perianth 

 segments narrow, reddish, acute; inner perianth segments white; areoles of 

 ovary and flower tube somewhat spiny ; fruit globular to short-oblong, 4 cm. 

 long, dull red. 



4. Acanthocereus occidentalis Britt. «& Rose, Cactaceae 2: 125. 1920. 

 Sinaloa, the type from San Bias. 



Stems rather weak, forming dense thickets ; branches slender, 4 to 5 cm. 

 in diameter, 3 to 5-angled, dull green, often bronzed ; margins of I'ibs slightly 

 sinuate ; areoles 1 to 3 cm. apart, filled with short brown wool ; spines nu- 

 merous, nearly equal, yellowish, acicular, up to 7 cm. long; flowers 14 to 18 

 cm. long. 



16. HELIOCEREUS Britt. & Rose, Contr. U. S. Nat. Herb, 12: 127. 1909. 



Stems usually weak, procumbent or climbing over rocks and bushes, in 

 cultivation often bushy and erect ; branches strongly angled or ribbed ; ribs 

 or angles usually 3 or 4, sometimes up to 7 ; spines of all areoles similar ; 

 flowers diurnal, large, funnelform, only 1 at an areole, usually scarlet, some- 



*The name "pitahaya" (also written " pitajaya," and "pitaya") is gen- 

 erally employed in Mexico for fruits of cacti of the Cereus alliance. Accord- 

 ing to Orozco y Berra, the Nahuatl name for plants of this group is " tzapo- 

 aochtli." Buelna reports the OtomI name as "bazttu " ; and Asiain the Huastec 

 aames as " oeomtzatza " and " tzalza." The name of the State of the Sinaloa 

 \s said to be derived from two Indian words, " sina," pitahaya, and " lobala," 

 found. 



