CACTACE^. (cactus FAMILY.) 171 



solitary sessile flowers. — Sepals and petals similar, imbricated in sev- 

 eral rows, and adherent to the 1-celled ovary. Stamens indefinite, 

 with long filaments, inserted on the base of the petals. Style single : 

 stigmas numerous. Fruit baccate. Seeds numerous, campylotropous, 

 borne on several parietal placentae. Albumen scanty or none. 



1. CEBEUS, Haw. 



Sepals and petals united into an elongated tube above the ovary. Stamens 

 inserted on the tube. Style filiform. Stigma mauy-lobed. Seeds without 

 albumen. — Stems elongated, ribbed or angled; the angles bearing tufts of 

 spines and showy flowers. 



1. C. monoclonos, DC. Stem tall, columnar, 6-8-angled, green; 

 angles obtuse; spines short, brownish. — Key West. — Stem 4°-10° high. 

 Flowers 6' long, the inner petals lanceolate, acuminate, white ; the outer ones 

 linear, greenish, and gradually diminishing into the scales of the tube. Stig- 

 mas 10 or more, filiform, exserted. Stamens included. 



2. C. triangularis, Haw. Stem elongated, jointed, 3-sided, rooting at 

 the joints ; flowers greenish externally, white within, very large ; fruit large, 

 naked. — Key West. — Stem climbing over bushes. Joints 1° long. 



2. OPUNTIA, Tourn. Prickly Pear. 



Sepals and petals not united into a tube. Stamens inserted into the base of 

 the petals. Style cylindrical. Stigma 3- 8-lobed. Seeds with thin albumen. 

 — Stems with flat or rarely cylindrical joints. Leaves fleshy, with tufts of 

 bristly hairs and commonly strong spines in their axils, deciduous. Flowers 

 large, yellow. 



1. O. FicUS-Indicus, Haw. Stem erect, spreading- joints oval and 

 obovate; leaves subulate, bristly in the axils, without spines; fruit bristly, ob- 

 ovate, red within, edible. — South Florida. May. — Joints 1° long. 



2. O. vulgaris, Mill. Stem prostrate ; joints obovate, pale ; spines few 

 and sliort ; fruit nearly smooth. — Dry sandy soil, near the coast. June- 

 July. 



3. O. Rafinesquii, Engelm. Stems spreading ; joints obovate or round- 

 ish, deep green ; leaves large, spreading ; spines stout, mostly marginal ; 

 flower buds acute ; petals 10- 12 ; stigmas 7-8. — Kocky or sandy soil, Ten- 

 nessee, and westward. 



4. O. polyantha, Haw. Stem erect; joints oblong; spines yellow, 

 strong, une(|u;il ; flowers numerous around the .summit of the joints ; stigmas 

 6. — Key West, and waste places around Apalachicola, Florida. June. 



5. O. Pes-Corvi, Leconte. Stems prostrate, diffuse ; joints small (1'- 3'), 

 cylindrical or somewhat flattened, easily separable, spiny; spines by pairs, 

 unequal, elongated ; sepals and petals 8-12, cuneate ; stigmas 4; fruit small, 

 fleshy, bristly, 1-2-seeded. — Barren .sandy places along the coast, Florida 

 and Georgia. May. — Stems 1*^-2° long. 



