i6o 



THE CACTACEAE. 



O. littoralis 

 O, aciculata 



Joints elongated-lanceolate or oblong, several times longer than wide i75- 0. linguijormis 



Joints obovatc to suborbicular. 

 Spines long. 



Areoles mostly 1.5 to 2 cm. apart. 



Spines subulate, up to 7.5 cm. long 176. 0. tapona 



Spines aciciilar, 4 cm. long or less. 



Spines nearly clear yellow, short 1 77- 



Spines brown at base, long and slender 178. 



Areoles mostly 2.5 to 4 cm. apart. 

 Bushy species. 



Spines yellow or yellowish brown I79- 0. liniheimeri 



Spines pale yellow or whitish 180. 



Depressed or procumbent plant 181. 



Spines only 1.5 cm. long or less, or becoming longer on old joints. 



Plant I meter high or less; joints thin 182. 0. Canada 



Plant 3 to 5 meters high; joints very thick. 



Spines reflexed; flowers yellow 183. 



Spines spreading, deciduous; flowers orange-red 183a. 



^. 



0, cantabrigiensis 

 0, procumbens 



0. pyriformis 

 0. bonplandii 



171. Opuntia chlorotica Engelmann and Bigelow, Proc. Amer. Acad. 3: 291. 1856. 



/ 



Opuntia tidhallii Bigelow, Pac. R. Rep. 4: 11. 1856. 

 Opuntia curvospina Griffiths, Bull. Torr. Club 43: 88. 



1916. 



Erect bushy, sometimes 2 meters high or more, with a definite trunk; main branches nearly 

 erect; joints ovate to orbicular, sometimes broader than long, 15 to 20 cm. long, more or less glau- 

 cous, bluish green; leaves subulate, small, reddish at tip; areoles closely set, prominent; spines 

 yellow, several, most of them usually appressed and reflexed, setaceous, 3 to 4 cm. long; glochids 

 yellow, numerous, elongated, persistent; flowers yellow, 6 to 7.5 cm. broad; filaments, white ; fruit 

 purple without, green within, 4 cm. long; seeds small. 





Fig. 199. — Opuntia chlorotica. 



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P^IG. 200. — Opuntia chlorotica. X0.4 



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waters of Bill Williams River. 



from San Francisco Mountains 



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Mexico to Nevada, California, and Lower 



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mesas 



mountain 



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Opuntia curvospina 



Torr 



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