432 
ish) and unequal (15 to 30 mm.), those on the face of the joint usually in 
pairs and detlexed, those on the margin apt to be in threes and erect- 
spreading, fruit dark-red and spineless (about 5 em. long), and seeds 
(4.5 to 5mm. broad) with conspicuous thick somewhat irregular mar- 
gin.—Type in Nat. Herb. 
Western Arizona. 
Specimens examined: ARIZONA (G. R. Vasey of 1881, Yuma; H. H. 
Rusby of 1883, Ft. Verde). 
41. Opuntia fusco-atra Engelm. Syn. Cact. 297 (1856). 
Diffuse, with orbicular-obovate tuberculate joints 6 to 7.5 em. long: 
pulvini 12 to18 mm. apart, with numerous short reddish-brown bristles, 
only the lower unarmed: spines mostly solitary, stout, suberect, brown- 
ish-black, 2.5 to 38 em. long, often one shorter deflexed one added: 
flowers yellow, 7.5 em. broad: fruit and seed unknown, (JUl. Pacif. 
R. Rep. iv. t. 11, f. 4)—Type, Lindheimer 33 of 1842 in Herb. Mo. Bot. 
Gard. 
“Sterile places in prairies west of Houston, Texas.” 
Specimens examined : TEXAS ( Lindheimer 33 of 1842). 
The stout brown (or above almost black) spines, and thick bunches of unusually 
stout brown bristles on small joints, give a characteristic appearance to the species. 
42. Opuntia opuntia (L.). 
Cactus opuntia L. Sp. Pl. i, 468 (1753). 
Opuntia vulgaris Mill. Dict. ed. 8, no. 1 (1768). 
Cactus humifusus Raf. Ann. Nat. i, 15 (1820). 
Diffuse and prostrate, with a fibrous root: joints obovate or suborbic- 
ular, thick, bright or pale green, 5 to 10 em. long by 5 to 6 em, broad, 
bearing ovate cuspidate mostly appressed leaves 4 to 5 mm. long: 
pulvini subremote, with few short greenish-yellow bristles, mostly 
unarmed: spines very rare, when present, solitary, stout, variegated, 
suberect, less than 2.5 cm. long: flowers pale-yellow, 5 em. broad: 
fruit obovate-clavate: seeds regular, thick, with thick margins, 5 mm. 
broad.—Type unknown, 
From the southeast coast of Massachusetts to Georgia and Florida; 
apparently only in the low countries east and southeast of the Alle- 
ghanies. 
Specimens examined: MASSACHUSETTS (Sprague, at Leyden): NEW 
York (Hex. & Maier of 1852): NEw JERSEY (Torrey & Gray of 
1846; Hex. & Maier of 1854; Meehan of 1876; Martindale of 1876): 
DELAWARE (Canby of 1861): VIRGINIA (Vasey of 1878, It. Monroe): 
SouTH CAROLINA (Mellichamp of 1871): also cultivated in numerous 
gardens. 
This species is distinguished from mesacantha (which only grows west of the Alle- 
ghanies and with which it has been confused) by its smaller size, paler color, small 
pulvini, usual absence of spines, smaller flowers, and especially by its short thick 
more or less appressed leaves. 
