OPUNTIACEAE 815 



3. Echinocereus F6ndleri (Engelm.) Small. Stems ovoid to cylindric-ovoid, 

 7.5-20 cm. high, 5-7.5 cm. thick, simple or branched at the base, the branches tufted, 

 the ribs 9-12, sometimes oblique, tuberculate: areolae less than 1.5 cm. distant: spines 

 short; radials 5-10, straight or sometimes curved, variable, lowest one 12-25 mm. 

 long, shorter than the rest, angled, the next 2 about as long or longer, more or less 

 blackish; succeeding ones shorter and weaker, 6-14 mm. long, occasionally accom- 

 panied by a spine at the top of the areolae surpassing all the rest in length; central 

 spine solitary, nearly terete, 2.5-5 cm. long, reddish black, upcurved from a bulb- 

 like base: flowers 6-8.5 cm. broad, deep violet purple: fruits 2.5 cm. long, purplish 

 green, edible: seeds less than 1.5 mm. long. [Cereus Fendleri Engelm.] 



In dry soil, Utah to Texas, Arizona and northern Mexico. 



4. Echinocereus Berlandi&ri (Engelm.) Small. Stems jointed, spreading, de- 

 cumbent, much-branched, the joints nearly terete, 3.5-15 cm. long, 2-2.5 cm. thick, 

 their ribs 5-6, with distinct tubercles: areolae quite close together: spines various; 

 outer white, 6-8, radiant, 8-10 mm. long; central solitary, 10-25 mm. long, yellowish 

 brown : flowers purple, 5-10 cm. long : fruits ovoid, nearly 2 cm. long, green, furnished 

 with bristles: seeds 1 mm. long, tuberculate. [Cereus Berlandieri Engelm.] 



In river valleys, southern Texas. 



5. Echinocereus procumbens (Engelm.) Small. Stems jointed, diffusely 

 branched, the joints nearly terete or 4-5-angled, 1.5-10 cm. long, 12-16 mm. thick, 

 contracted at the base, with 4 or 5 rows of distinct tubercles: spines rigid, rather 

 slender; outer white, radiant, 5 or 4-6, 2-4 mm. long; central solitary, stouter than 

 the outer, 4-6 mm. long, ascending or wanting: flowers delicate purple, fully 7.5 cm. 

 long: fruits green, ovoid, 12-16 mm. long: seeds lenticular, nearly 1 mm. thick. 

 [Cereus procumbens Engelm.] 



In river valleys, southern Texas. 



4. WILCOXIA Britton & Rose. 



Plants fleshy with weak erect or reclining ribbed stems and branches, the areolae 

 with equal or nearly equal spines. Leaves obsolete. Flowers diurnal, relatively large, 

 one only from an areola. Hypanthium rather short, slightly broadened upward, the 

 areolae with both spines and wool. Sepals and petals mostly rose or purple. Fruits 

 fleshy, the areolae with spines. 



1. Wilcoxia Foselgeri (Lem.) Britton & Rose. Stems weak, erect or reclining, 

 sparingly branched, the joints slender, 30-60 cm. long, 8-16 mm. thick, the ribs 8, 

 not very prominent, furnished with closely set areolae : spines bristle-like ; outer white, 

 9-12, straight, barely 2 mm. long; central solitary, 4-6 mm. long, whitish to brown 

 or black: flowers rose or purple, 5 cm. long and broad: fruits about 2 cm. long, 

 clothed with white and black bristles and wool: seeds less than 1 mm. long, tubercu- 

 late. [Cereus Poselgeri Coulter, Echinocereus Poselgeri (Coulter) Lem.] 



On rocky ridges, southern Texas and adjacent Mexico. 



5. HYLOCEREUS Britton & Rose. 



Plants fleshy with climbing 3-angled or 3-winged stems and branches, with aerial 

 roots, the areolae with several short spines and a tuft of short wool. Leaves obsolete. 

 Flowers nocturnal, very large. Hypanthium trumpet-shaped, with foliaceous scales, 

 without spines or wool. Sepals various, the outer ones resembling the hypanthium- 

 scales, the inner resembling the petals. Petals narrow, mostly white. Fruits fleshy, 

 globose or ovoid, with broad scales. 



1. Hylocereus triangularis (L.) Britton & Rose. Stems reclining or procum- 

 bent, elongated, branched, the branches often rooting at the joints, 3-angled or with 

 a flat side and 2 grooved sides, the joints commonly 32 cm. long, 5-7.5 cm. broad, 

 occasionally twisted, the ribs at first wing-like, with remote areolae: spines 3-5. 

 rigid, blackish, somewhat recurved, 2-4 mm. long, upper ones shorter than the lower: 

 flowers white, 20 cm. broad: fruits ovoid, commonly 10 cm. long, scarlet. [Cereus 

 triangularis (L.) Haw.] 



In hammocks, peninsular Florida, the West Indies and Central America. 



6. ACANTHOCEREUS Britton & Rose. 



Plants fleshy with erect, reclining or climbing 3-6-angled stems and branches, 

 without aerial roots, the areolae with several rigid spines and a tuft of short wool, 



