NYCTOCEKIHS. 



117 



fruit is called pitahaya agre or pitahaya agria and is probably the most valuable fruit of 

 Lower California. A fish poison is prepared by bruising the stems. The mashed pulp 

 is then thrown into a running stream. 



Fig. 174. — Machaerocereus gummosus. 



Fig. 175.— Flo 

 of M. gumi 

 sus. X0.6. 



Cereus gummatus, C. gumminosus, and C. pfersdorffii Hildmann (Schumann, Gesamtb. 

 Kakteen 125. 1897) are only garden names of this species. 



Illustrations: Grassner, Haupt-Verz. Kakteen 3; Monatsschr. Kakteenk. 13: 105, 

 both as Cereus gummosus; Contr. U. S. Nat. Herb. 16: pi. 126 A, as Lemaireocereus 

 gummosus. 



Figure 173 is from a photograph of a plant collected by Dr. Rose at Santa Maria Bay 

 in 191 1 ; figure 174 is from a photograph taken by E. A. Goldman on Esperito Santo 

 Island, Lower California, in 1906; figure 175 shows a flower drawn from an herbarium 

 specimen obtained from C. R. Orcutt, collected in northern Lower California. 



20. NYCTOCEREUS (Berger) Britton and Rose, Contr. U. S. Nat. Herb. 12: 423. 1909. 



Erect or clambering, slender, sparingly branched cacti, with cylindric, ribbed stems and branches; 

 ribs numerous, low; areoles each bearing a tuft of short white wool and small radiating acicular 

 bristles or weak spines; flowers large, white, nocturnal; ovary bearing small scales, short or long wool, 

 and tufts of weak spines or bristles; perianth funnelform, gradually expanding above, bearing scales 

 and tufts of weak bristles below the middle, above the middle bearing narrowly lanceolate scales 

 distant from each other and grading into the blunt outer perianth-segments ; inner perianth-segments 

 widely spreading, obtuse or acutish; stamens numerous, shorter than the perianth; style about as 

 long as the stamens; fruit fleshy, scaly, spiny or bristly; seeds large, black. 



Type species: Cereus serpentinus De Candolle. 



Nyctocereus was considered by A. Berger a subsection of his subgenus Eucercus but his 

 conception of it was of a complex, from which we would exclude all but three of the species 

 which he referred to it. He speaks of certain forms in the type species which have smaller 

 flowers and no fruit; this variation we have also noticed in N. guatemalensis. 



The name is from the Greek, meaning night-cereus. Five species are here recognized, 

 natives of Mexico and Central America. 



