Opuntia. CACTACEJ3. 249 



ivory-white seeds. — Nutt. in Ton. & Gray, Fl. i. 155. 0. erinacea, Engelm. & 

 Big. Cact. 1. c. 47, t. 13, fig. 8- 11. 



From the Mohave region (Bigelow) to Southern Utah (Palmer), and up the Colorado A'allcy, 

 Nuttall. This plant seems to be Nuttall's long-lost 0. rutila, and also 0. erinacea of the 

 Mohave, the flower of which is unknown. Joints 2 to i inches long, 1A to 3 wide, and often, 

 especially in young plants, thick and almost terete, thus approaching to 0. f myitis: seeds 3 

 lines wide. 



■h- +- Joints and fruit p>nbescent, without spines. 



6. O. basilaris, Engelm. & Big. Low, with obovate often retuse or fan-shaped 

 joints, branching only from the base : areolae very close, densely covered with short 

 brown bristles : flowers large, rose-purple : fruit subglobose, with deep umbilicus, 

 and rather few large and thick seeds. — Cact. 1. c. 43, t. 13, fig. 1 - 5. 



From the eastern base of the mountains near San Felipe through the desert and into Arizona, 

 Bigelow, Xewbcrry, Palmer, &c. Joints a to 8 inches long, and often as wide near the top ; dis- 

 tinct from all other species of this region in its mode of growth, its pubescence, absence of spines 

 proper, and its very large seeds (3J to 5 lines wide), which have a thicker but less prominent rim 

 than any other of this section. 



§ 2. Joints cylindrical, more or less tubercidated : rhaphe •usually not prominent, 

 therefore seed not margined : embryo forming less than one circle around the 

 more copious albumen ; cotyledons inconstant, contrary, oblique, or parallel to 

 the sides of the seed. — Cyuxdkopuntia. 



* Low plants with clavate joints, without a firm ligneous skeleton : larger spines 



angular-compressed, without sheaths : berries dry and very bristly. 



7. O. Emoryi, Engelm. Joints long, clavate-cylindrical, with linear-oblong and 

 very prominent tubercles : spines numerous (15 to 30) in the upper bundles, the 

 5 to inner ones stouter, angular-compressed : seeds large, irregular, the rhaphe in- 

 distinct. — Cact. Mex. Bound. 53, t. 70, 71. 



Colorado desert from San Felipe (Parry, Bigelow) eastward, and into Aiizona (SchoU, Palmer) 

 and the Peninsula, Oabb. Joints 5 to 9 inches long, 1 to 1A thick; tubercles 1 to 1A inches 

 long ; fruit 2 to 2A inches long ; seeds 2J to 3 lines wide. 



8. O. Parryi, Kngelm. Joints short, ovate-clavate with oblong tubercles : spines 

 12 to 20, reddish gray, the 3 or 4 inner ones stouter, triangular-compressed : seeds 

 smaller, regularly circular, with a broad and distinct rhaphe. — Am. Jour, s, i. i' scr. 

 xiv. 339 ; Cact. of Pacif. R. Rep. iv. 48, t, 22, fig. 4-7. 



Gravelly plains near the Mohave River (Bigelow), and through the desert to the base of the 

 mountains, Parry. Joints 3 or 4 inches long, 1J thick ; tubercles about j inch long. 



* 9. O. pulchella, Engelm. Joints smaller, slender : tubercles small: spines 1"> 

 to 2."), of which usually ono only is stouter, flattened, deflcxed : llowvrs purple : 

 ovary and fruit with long flexuous bristles: seeds small, with a broad rhaphe. — 

 Trans. Acad. St. Louis, ii. 201 ; Boi King Exp. 119 ; fig, in Simpson Rep. ined. 



Sandy deserts of Southeastern California and Nevada, and among the sage-bushes of the moun- 

 tains, 11. Engelmann, II'. Oabb, Watson. The prettiest and smallest of the clavate Oprmlice, 

 the only one with purple flowers ; joints rarely longer than 1 or 2 inches ; Dowers 1 } to M, inches 

 wide ; seeds 2 lines in diameter. 



* • More or less erect, ma.h bram-lnd : joints cyliadrie : ligneous skeleton solid or 



tubular and reticulated ' : larger S2>ines terete, coated with a louse sfieath. 



+- Fruit dry and s/tiiiy : flowers yellow. 



10. O. tessellata, Engelm. Much branched, bushy, from a stout ligneous 

 trunk : joints slender, covered with angular flattened ashy-gray tubercles, bearing 

 above long single loosely sheathed spines: flowers small, yellow : small oval fruit 

 covered with long brown bristles: seeds with a verj broad Bat rhaphe. — fact, of 

 Pacif, R. Rep. iv. 52, t. 21. 



