DICOTYLEDONOUS PLANTS 155 



when ripe, eatable. Dry rocks and sandy ground, from Massachu- 

 setts south along the coast. 



2. 0. Rafinesquii, Engelm. Prostrate, green. Leaves - in. long, 

 awl-shaped, spreading ; bristles often intermixed with a few small 

 spines and a larger one f-1 in. long. Flowers larger than in No. 1 

 and with 10-12 petals. Fruit about 1| in. long, much tapered at 

 the base. In poor soil. 



3. 0. missouriensis, DC. Prostrate, light green. Leaves very 

 small, with bristles and 5-10 spines in their axils. Flowers 2-3 in. 

 in diameter. Fruit dry and spiny. Wisconsin, S. and W. 



I 

 II. PHYLLOCACTUS. 



Stems cylindrical when old, with long, flattened, fleshy but 

 leaf-like, sinuate or serrate branches. Flowers nearly or quite 

 regular, from the notches in the margins of the joints. 



1. P. Ackermanni, L. Flowers very showy, bright red. Perianth- 

 tube shorter than the petals. Sepals scattered, small and bract-like. 

 Petals many, 2-3 in. long, widely spreading, somewhat channeled, 

 sharp-pointed. Cultivated from Mexico. 



III. CEREUS, DC. 



Stem more or less prismatic but strongly ridged, with bun- 

 dles of spines borne on the ridges, sometimes prostrate or 

 trailing, sometimes erect, columnar, and 50 or 60 ft. high. 

 Flowers usually showy, borne on the sides of the stem, gener- 

 ally with a rather long perianth-tube, which is covered outside 

 with scale-like sepals, usually with tufts of wool in their axils. 

 Petals many, mostly long and spreading. 



1. C. speciocissimus, DC. Stems 2-3 ft. high, with 3-4 broad- 

 winged and sinuate ridges. Flowers open in the daytime and lasting 

 several days, red or crimson, very showy. Petals longer than the 

 tube, stamens white, drooping, very numerous. Commonly culti- 

 vated from Mexico. 



2. C. grandiflorus, Mill. NIGHT-BLOOMING CEREUS. Stems long, 

 climbing by aerial roots, nearly cylindrical, but with 5 or more blunt 

 angles. Flowers very showy, opening only for one night, wilting 

 early in the morning, extremely fragrant. Sepals dull yellow. Petals 

 pearly white, spreading, 6-8 in. long. Cultivated from Mexico. 



