CACTACE.E 757 



oblong, orange-colored, surmounted by the rounded thickened end of the connective, those 

 of the inner row almost sessile and one third larger than those of the outer row, shorter than 

 their flattened filaments covered, like the connectives, with long slender white hairs; pistil- 

 late flowers about 1' long, with erect petals, without staminodia; ovary ovoid, ivory-white, 

 slightly and obtusely 5-angled, 1-celled, and narrow r ed into a short slender style crowned 

 by a pale green stigma divided to the base into 5 radiating lobes dilated and 3-nerved at 

 apex. Fruits hanging close together against the stem at the base of the leaf-stalk, ob- 

 ovoid to ellipsoid, and obtusely short-pointed, yellowish green to bright orange color; in 

 southern Florida not more than 4' long and 3' thick, and usually smaller, with a thick skin 

 closely adherent to the sweet insipid flesh forming a thin layer outside the central cavity; 

 seeds full and rounded, about T V long; outer portion of the seed-coat rugose at first when 

 the fruit is fully grown but still green, ivory-white, very succulent, and usually separable 

 from the smooth paler chestnut-brown lustrous interior portion, the outer part turning 

 black as the fruit ripens and becoming adherent to the inner portion closely investing the 

 thin lustrous light red-brown inner coat. 



A short-lived tree, in Florida attaining a height of 12-15, with a trunk seldom more 

 than 6' in diameter; in the West Indies and other tropical countries often twice as large, 

 with a trunk occasionally dividing into a number of stout upright branches. Bark thin, 

 light green, becoming gray toward the base of the stem. 



Distribution. Florida from the southern shores of Bay Biscayne on the west coast and 

 of Indian River on the east coast to the southern keys, growing sparingly in rich hum- 

 mocks; common in all the West Indian islands, in southern Mexico, and in the tropical 

 countries of South America; now naturalized in most of the warm regions of the world, 

 where it is universally cultivated for its fruit, which is considered one of the most whole- 

 some of all tropical fruits, and has been much improved by selection. 



XLV. CACTACEJE. 



Succulent trees or shrubs, with copious watery juice, numerous spines springing from 

 cushions of small bristles (areolce), and minute caducous alternate leaves, or leafless. 

 Flowers large and showy, perfect, usually solitary; calyx of numerous spirally imbricated 

 sepals forming a tube, those of the inner series petal-like; corolla of numerous imbricated 

 petals, in many series; stamens inserted on the tube of the calyx, very numerous, in several 

 series, with slender filaments and introrse 2-celled oblong anthers, the cells opening longi- 

 tudinally; pistil of several united carpels; ovary 1-celled, with several parietal placentas; 

 styles united, terminal; stigmas as many as the placentas; ovules numerous, horizontal, 

 anatropous. Fruit a fleshy berry. Seeds numerous, with albumen; cotyledons foliaceous; 

 radicle turned toward the hilum. 



The Cactus family with twenty genera and a very large number of species is most abun- 

 dant in the dry region adjacent to the boundary of the United States and Mexico, with a 

 few species ranging northward to the northern United States and southward to the West 

 Indian islands, Brazil, Peru, Chili and the Galapagos Islands. Two of the genera have 

 aiborescent representatives in*the flora of the United States. 



CONSPECTUS OF THE ARBORESCENT GENERA OF THE UNITED STATES. 



Branches and stems columnar, ribbed, continuous; leaves 0; flower-bearing and spine- 

 bearing areolse distinct; flowers close above spine-bearing areolse; tube of the flower 

 elongated; seeds dark-colored. 1. Cereus. 



Branches jointed, tuberculate; leaves scale-like; flower-bearing and spine-bearing areolae 

 not distinct; tube of the flower short and cup-shaped; seeds pale. 2. Opuntia. 



1. CEREUS Haw. 



Trees or shrubs, with columnar ribbed stems, and buds on the back of the ridges from 

 the axils of latent leaves, geminate, superposed, the upper producing a branch or flower, the 



