248 CACTACE^. Opuntia. 



§ 1. Joints compressed : rhaphe fowling a prominent hony margin around the seed : 

 embryo completing a little more than one circle aroxmd the scanty albumen ; 

 cotyledons contrary to the sides of the seed. — Platopuntia. 



* Fi'uit pidpy. 



1. O. Engelmanni, Salm. Bushy, erect-spreading, much branched : obovate 

 joints \ to 1 loot long, sparsely armed with bundles of 1 to 3 or sometimes even 5 

 spines, the stouter ones angled, yellow, sometimes with a red-brown base; old trunks 

 losing their spines : flowers yellow, about 3 inches wide : petals broadly obovate, 

 truncate : the purple oval juicy berry about 2 inches long, with a large flat um- 

 bilicus, and with- 20 to 25 brown-woolly and slightly bristly areolae. — Salm. Cact. 

 cult. 1849, 235 ; Engelm. Cact. Mex. Bound. 47, t. 75, fig. 1 - 4. 



Var. /3. occidentalis, Engelm. Spines fewer, stouter, farther apart : seeds 

 larger. — 0. occidentalis, Engelm. & Big. in Cact. of Pacif. li. Pep. iv. 38, t. 7. 



Var. (])y. littoralis, Engelm. Joints often larger, 1 to IJ feet long: bunches 

 of longer and more slender spines closer together : fruit similar, but with 40 to 50 

 areola? : seeds smaller. 



Apparently a poljniiorphous species, extending fi-om Southern Texas to the Pacific, which will 

 ]iiolial)ly be iilcutitied with some older Mexican species when these plants come to be better 

 undcrwtood. The two forms of California are easily distinguished by the characters given above. 

 The var. ucciilrntdlis lias been found on the western slope of the mount;rins east of Los Angeles 

 and southward to San Isabel, etc., at an elevation of 1,000 to 2,000 feet, Parry, Schott. The 

 areohe of the joints are 1^ to 2 inches apart ; spines | to 1^ inches long ; flowers 3 to 3^ inches 

 wide, yellow with orange centre ; fruit often 1^ inches thick ; seeds 2h to 2f lines wide. The 

 second foini, var. littoralis, extends on the coast from Santa Barbara and the islands in its gulf 

 (0. Tittvmmi) to San Diego, and southward, G. N. Hitchcock. Seeds 2 to 2^ lines in diameter. 



— The limits of these species are difficult to circumscribe, especially because complete speci- 

 mens are so hard to preserve and extensive observations in the field have not yet been made. Of 

 the three following no more is known now than there was twenty years ago. 



2. O. chlorotica, Engelm. & Big. Erect, bushy ; old trunks covered with 

 large areohe wliich, retaining their vitality, constantly produce new spines ; joints 

 large, pale green, orbicular-obovate, with close-set areola', each bearing 1 to 5 slender 

 deflexed yellow spines : flowers yellow, 2.^ to 3 inclies wide, with spatulate petals. 



— Cact. of Pacif. P. Pep. iv. 38, t. 6, fig. 1 - 3. 



From Mohave Creek eastward to Bill Williams Mountain in Arizona (Bigelotv) ; 4, 5, or even 7 

 feet liigh, I'eadily recognized by the very spiny trunk and very pale broad joints f to 1 foot long. 



3. O. angustata, Engelm. & Big. Prostrate or ascending, with obovate elon- 

 gated joints : large oblong areoltB sparse, bearing brown bristles and few (1 to 3) 

 deflexed spines : fruit rather small, deeply umbilicate, with few large seeds. • — Cact. 

 1. c. 39, t. 7, fig. 3, 4. 



From Cajon Pass eastward into Arizona, Bigeloiv. Joints 10 inches long or more, not half as 

 wide above, nan'owed 'downward ; berry 1^ inches long, narrow ; seeds 3 lines wide. 



4. O. Mohavensis, Engelm. & Big. Prostrate, ^vith large nearly orbicular 

 joints, and more numerous (2 to G) stout and long often curved brown spines. — 

 Cact. 1. c. 40, t. 9, fig. 6-8. 



On Mohave Creek, Bigeloiv. A doubtful form, of which flowers and frait are unknown. It 

 seems to approach 0. 'phmacantha of New Mexico, and perhaps even the stouter western forms 

 of 0. Rafincsqiiii. It is indicated here merely for the attention of future explorers. 



O. Tuna and 0. Ficus-Indica, Mill., are probably both naturalized about the old missions ; 

 one with stout yellow spines and insipid fruit, the last with weaker whitish spines, fruit delicious. 



-J- Fruit dry. 



-}•+ Joints and fruit spiny. 



5. O. rutila, Xutt. Prostrate, with thick obovate or elongated joints : areole 

 close, aruu'il with numerous slender reddish or gray flexible spines : large flowers 

 purple : stigmas green : berry dce[ily uiuldlicate, with large Hat broadly margined 



