758 



TREES OF NORTH AMERICA 



lower arrested and developed into a cluster of spines surrounded by an elevated cushion or 

 areola of chaffy tomentose scales. Flowers lateral, elongated, the calyx-lobes forming an 

 elongated tube, those of the outer ranks adnate to the ovary, scale-like, only their tips free, 

 those of the inner ranks free, elongated; petals cohering by their base with the top of the 

 calyx-tube, larger than its interior lobes, spreading, recurved; stamens numerous; filaments 

 adnate by their base to the tube of the calyx, those of the interior ranks free, the exterior 

 united into a tube; style filiform, divided into numerous radiating linear branches stigmatic 

 on the inner face; stalks of the ovules long and slender, becoming thick and juicy in the 

 fruit. Seeds with very thin albumen; embryo straight: cotyledons abbreviated, hooked at 

 apex; radicle conic. 



Cereus with at least two hundred species inhabits the dry southwestern region of North 

 America, the West Indies, tropical South America, and the Galapagos Islands. Of the nu- 

 merous species found within the territory of the United States only one assumes the habit 

 and size of a tree. The fruit of several species is edible, and the ribs of the durable woody 

 frames of the stems of the large arborescent species are used for the rafters of houses and 

 for fuel. Many of the species are planted in warm dry countries in hedges to protect cul- 

 tivated fields, and others are popular garden plants valued for their beautiful flowers, 

 which are sometimes nocturnal and exceedingly fragrant. 



The generic name relates to the candle-like form of the stem of some of the species. 



1. Cereus giganteus Engelm. Suwarro. 



Leaves 0. Flowers 4'-4' long and 2|' wide, opening from May to July in great numbers 

 near the top of the stem, each surrounded on the lower side by the radial spines of the cluster 

 below it; ovary ovoid, 1' long, rather shorter than the stout tube of the flower, and covered, 



Fig. 682 



like the base of the tube, by tne thick imbricated green outer scale-like sepals, with small 

 free triangular acute scarious mucronate tips, furnished in their axils with short tufts of 

 rufous hairs and occasionally with clusters of chartaceous spines, gradually passing into thin 

 oblong-ovate or obovate larger sepals, mucronate or rounded at apex and closely imbricated 

 in many ranks; petals 25-35, obovate-spatulate, obtuse, entire, thick and fleshy, creamy 

 white, f long and much reflexed after anthesis; stamens, with linear anthers emarginate 

 at the ends, and filaments united for half their length to the walls of the calyx-tube, those 

 of the exterior rows joined below into a long tube, surrounding the stout columnar style 

 glandular at base and divided at apex into 12-15 green stigmas. Fruit ripening in August, 

 ovoid or slightly obovoid, 2^' long and l' wide, truncate and covered at apex by the de- 

 pressed pale scar left by the falling of the flower, light red at maturity, separating into 3 or 4 



