250 FICOIDE.E. Opuntia. 



Throughout the Californian desert from the mountains to the Colorado, and into Arizona. 

 Bushes 4 to 6 feet high ; trunk solid, sometimes 2 inches in diameter ; joints only ^ or J inch 

 thick ; spines an inch or two long ; flowers 6 to 9 lines wide ; fruit 9 lines long ; seeds 2 lines 

 wide. 



11. O. echinocarpa, Engelm. & Big. A low much-branched and spreading 

 shrub : joints ovate-clavate, densely covered with numerous spines (3 or 4 stouter, 

 8 to 16 weaker ones in a bunch), which are loosely coated with a whitish glistening 

 sheath : flowers pale greenish yellow, about 1| inches wide : fruit depressed, deeply 

 umbilicate, very spiny : seeds few (2 lines wide), with a broad flat rhaphe. — Cact. 

 1. c. 51, t. 18, flg. 5 - 10 ; Bot. Ives Colorado Exp. 14. 



Common in the desert from the mountains to the Colorado River, and into Ari2ona. Usually 

 only 1 to 1^ feet high, very showy from its conspicuous shining spines, an inch or two long. 



12. O. serpentina, Engelm. A large straggling densely branched shrub: joints 

 elongated, covered witli oblong prominent tubercles, which bear bunches of numer- 

 ous short spines, very soon losing their inconspicuous sheaths : flowers chistered, 

 greenish yellow, reddish externally : petals spatulate, obtuse : stigmas 8, whitish : 

 iruit broadly oval, deeply umbilicate : seeds thick, irregular, with a narrow rliaphe. 

 — Am. Jour. Sci. 2 ser. xiv. 338. 



Common near the coast, at San Diego, Parry, Hitchcock. Bushes 3 to 5 feet high ; spines 

 8 to 15 in a bunch, 3 to 6 lines long ; flowers IJ inches wide ; fruit about 9 lines long. 



-i-+ Fruit green, fleshy, and without spines : floivers red. 



13. O. prolifera, Engelm. An arborescent shrub with elongated joints, covered 

 with oblong obtuse tubercles, which bear 3 to 6 or 8 spines, obscurely sheathed : 

 floAvers densely clustered at the ends of the branches, small, brick-red : fruit clavate, 

 obovate, or subglobose, strongly tubercled, deeply uudjilicate, almost always sterile 

 and often proliferous : seeds large, regular, with a broad j^rominent rliaphe. — Am. 

 Jour. Sci. 1. c. 



San Diego {Parry, Schott, Agassiz), up the coast to San Buenaventura, and southward 

 into the Peninsula, Gabh. Larger than the last, with stouter more strongly tubercled joints, 

 and fewer and shorter spines, and easily distinguished from it in flower and finiit : longest spines 

 1 to H inches long ; flowers \h inches wide ; seeds 3 lines in diameter, with a more prominent 

 and broader rhaphe than its allies. 



Several other Opuntia;, belonging to this last section, all with red flowers and fleshy fruit, are 

 found in Western Arizona and may also be expected on the western side of the Colorado. They 

 are all erect much-branched bushes, covered with shining sheathed spines. The more northern 



0. BiGELOvii, Engelm., has short tubercles. 



0. FTJLGENs, Engelm. & Big., and 0. mamill.a.ta, Schott, both south of the Gila (perhaps 

 forms of a single species), have very prominent tubercles, and small curiously irregular seeds 

 1^ to 2 lines long, with a linear rhaphe. 



0. LEPTOCAULis, DC, including 0. frutescens, Engelm., 0. vaginata, Engelm., and several 

 other synonyms, is the slenderest of all Opuntia;, with long branches scarcely thicker than a 

 goose-quill, small yellow flowers, and a small pulpy scarlet fruit ; common throughout all 

 Northern Mexico, ranging into Texas, New Mexico, and Western Arizona, and may also be 

 found west of the Colorado River. 



Order XLIV. FICOIDE^. 



A miscellaneous group, chiefly of fleshy or succulent plants, with mcstly opposite 

 leaves and no stipules ; differing from Caryophyllacea' and Portidacacece by having 

 distinct partitions to the ovary and capsule (which are therefore 2 - many-celled) ; 

 the petals and stamens sometimes numerous in the manner of Cadacece (but the 

 former wanting in most of the genera) ; agreeing with all these orders in the campy- 

 lotropous or amphitropous seeds ; the slender embryo curved partly or completely 

 round a mealy albumen. 



