242 ; CACTACEA, CACTUS — 
OPUNTIA. 
1. Cactus. Globose or oval plants without proper leaves, covered with 
spine-bearing tubercles; spines never barbed: flowers sessile, solitary, 
from between the tubercles. 
2. Opuntia. Branching or jointed spiny plants with subulate fearly ~ 
deciduous leaves: spines always barbed: flowers from the same areola 
as the spines. 
1 CACTUS L. Sp. Pl. 466. in part. 
MAMALARIA Haw. 
Roundish or somewhat cylindrical plants, destitute of woody 
axis, often with a somewhat milky juice, covered with conical 
.or mammeeform crowded spirally disposed tubercles which bear 
deciduous spines and tomentum at their extremity. Flowers 
sessile among the tubercles usually in a transversezone. Tube of 
the calyx adherent to the ovarv, the lobes 5-6 crowning the 
young fruit colored; petals 5-6 scarcely distinct from the calyx, 
longer than the sepals and united with them into a tube.  Sta- 
mens filiform, in several series. Styles filiform; stigma 5-7- 
cleft, radiate. Fruit smooth, : 
C. viviparus Nutt. Fraser’s Catalogue. Cespitose, the glomerules 
subglobose: tubercles cylindric-ovate, bearded, marked above with a pro- 
liferous groove; flowers bright red, large, exserted, exterior segments of 
the calyx ciliate; fruit filiform, greenish. On summits of gravelly hills, 
Eastern Cregon to British Columbia, east to Missouri. 
2. OPUNTIA Mill. Gard. Dict. ed. 6. 
Shrubby plants with articulate branches, the joints mostly 
compressed and dilated, bearing fascicles of prickles or bristles 
arranged in a quincuncial or spiral order; flowers arising from 
the clusters of prickles or along the margin of thejoints. Sepals 
and petals numerous, adnate to the ovary, not produced into a 
tube, the interior petaloid. Stamens numerous, shorter than 
the petals. Style cylindrical constricted at the base, stigmas 
numerous, thick, erect. Fruit umbilicate at the apex, tubercu- 
late, often prickly. 
0. polyacantha Haw. Suppl. Succ. 82. 0. Missouriensis DC, Pros- 
trate, forming large spreading masses: joints light-green, orbicular, tuber- . 
culate, 4-8 inches long: leaves minute, 2-3 lines long: pulvina 6-8 lines 
apart, with reddish-brown bristles, all armed: spines 8-15, the 5-10 ex- 
terior radiant, setiform, whitish or reddish variegated; the 3-5 interior ones 
stout, reddish-brown, 1-2 inches long, 2-4 of them deflexed, the other one 
spreading or suberect and very stout: flowers yellow or sometimes purple; 
stigmas 5-8; fruit ovate, dry and spiny, with shaliow flat umbilicus, 1-2 — 
inches long: seeds irregular, large. Plains and mountains, Eastern Wash- 
ington to beyond the Rocky Mountains, 
Var. platycarpa Coulter Rey. Cact. 436. Joints elongated-obovate {to 
obovate-orbicular, 3-5 inches long: pulvina 6-9 lines apart, with few 
straw-colored bristles, the lower ones unarmed or upper ones with few 
spines, or with exterior spines as in the species and mostly 1 stout spread- 
ing or deflexed reddish-brown interior one: fruit depressed-globose with a 
He enacted large and flat umbilicus, 4-9 lines long. Idaho to the Upper 
issouri. 
