816 OPUNTIACEAE 
colored to red, straight or curved, deflexed or spreading: flowers yellow within, red with- 
out, 6-7.5 cm. broad: fruit globose-obovoid or nearly so, 5 cm. long, purplish without, the 
pulp insipid or nauseous: seeds 3-4 mm. long, margined. 
In valleys, Texas to California and Mexico. 
4. Opuntia tortíspina Engelm. Stems procumbent, the branches ascending, the 
joints orbicular-obovate, 15-20 cm. long, with cushions or yellowish bristles, 2.5-3.5 cm. 
distant: spines white, 3-5 together, 3.5-6 cm. long, angled, channeled, often spirally 
twisted, accompanied by 2—4 spines about 4 as long, below them: flowers sulphur-yellow, 
6-7.5 cm. long: seeds suborbicular, 4-6 mm. broad. 
On plains, Nebraska to the Indian Territory and Texas. 
5. Opuntia grandiflora (Engelm.) Small. Stems ascending, branching, the joints 
suborbicular to obovate, 12-15 em. long, bright green : bristle-cushions remote, the bristles 
slender : spines sometimes wanting or obsolete : flowers yellow except the red center, 11- 
12.5 em. broad: fruit narrowly club-shaped, 6 cm. long: seeds 5-6 mm. broad. [0O. 
Rafinesquei var. grandiflora Engelm. ] 
In sandy soil, along the Brazos River, Texas. 
6. Opuntia macrorhiza Engelm. Stems prostrate or ascending from fusiform or 
thick-tuberous roots, the joints narrowly obovate or oblong-obovate, bright green, 5-8 
cm. long, with smallleaves about 10 mm. long: bristle-cushions remote, near the base or 
margins of the joints, the bristles yellowish brown: spines scattered over the joints or 
chiefly near the top, solitary or 2-3 together, white or variegated, slender, spreading or 
deflexed : flowers pale yellow, red at the base, 5-7.5 cm. broad: fruit obovoid, green or 
pale purple, 3.5 cm. long: seeds 5 mm. thick, acute-margined. 
In sterile soil, Kansas to Arkansas, Texas and Arizona. 
7. Opuntia austrina Small. Stems more or less spreading, shrubby at the base, from 
tuberous roots, the joints broadly obovate or orbicular-obovate, deep green, 5-11 em. long, 
or rarely somewhat longer, with early deciduous leaves mostly less than 10 mm. long: 
bristle-cushions chiefly near the margins of the joints, the bristles sordid or tawny : spines 
above the middle of the joints and near the edge, usually 2 together but one of them very 
small or deciduous, whitish or pinkish and reddish near the base and apex, twisted: 
flowers bright yellow, 6-7 cm. broad: petals cuneate, truncate or retuse at the slightly 
eroded top, and mucronate: fruit 2.5-3 cm. long. 
In eoral sand, southern peninsular Florida and the Keys. 
8. Opuntia humifüsa Raf. Stems prostrate, from fibrous roots, diffusely spreading, 
the joints obovate to suborbicular, 7.5-12 cm. long, deep green, with subulate leaves often 
6-8 mm. long : bristle-cushions remote, with reddish brown bristles, usually unarmed, or 
spines few, straight, whitish oroften reddish at the base and apex, terete, mostly marginal, 
1.5-2.5 em. long, straight: flowers sulphur-yellow and often reddish in the center, 6-8. 
cm. broad: fruit club-shaped, 3.5 em. long, barely 3 as thick with an edible us acid 
or sweetish pulp: seeds 5 mm. broad, flattened, acutish margined.  [O. Rajinesquet 
Engelm.] 
In sandy or rocky soil, Minnesota to Missouri, Kentucky and Texas. 
9. Opuntia füsco-àtra Engelm. Stems diffusely branched, the joints orbicular- 
obovate, 6-7.5 cm. long, tuberculate : bristle-cushions rather remote, tomentose, the upper 
one unarmed, the bristles reddish brown: spines brownish black, usually solitary, 2.5- 
cm. long, short, rather erect, an additional short deflexed one sometimes present : flowers 
yellow, 7.5 cm. broad : fruit unknown. 
In sterile soil or on prairies, Texas. 
10. Opuntia Opúntia (L.) Coulter. Stems prostrate or diffusely ascending from 
fibrous roots, the joints orbicular to obovate, pale or light green, 5-10 em. long, sie 
thick leaves 4-5 mm. long: bristle-cushions rather remote, usually unarmed : bristles urb 
yellowish green : spines few, when present solitary, less than 2.5 cm. long, variegate di 
flowers pale yellow, 5-6 cm. broad: fruit obovoid or clavate-obovoid, 2-3 cm. long : see 
9 mm. long, thick-margined. [O. vulgaris Mill.] 
In sand or sandy soil, or on rocks, Massachusetts to Florida and Alabama. Spring to fall. 
11. Opuntia Pès-Còrvi LeConte. Stems prostrate or diffusely spreading, 3-7 on 
long, the joints narrowly ovoid to obovoid, nearly terete, 2.5-7.5 cm. long, light pee 
loosely attached to each other: bristle-cushions quite numerous, the upper ones armec, flat- 
bristles pale : spines slender, solitary or 2-3 together, straight, 2.5-3.5 cm. long, s ak 
tened at the base and twisted : flowers yellow, 3.5-4 cm. broad : fruit oboyoid, 12-15 mm. 
long, rose-purple, bristly: seeds often 4-5 mm. long, with an obtuse margin. 
On sandy coasts or adjacent ridges, Georgia and Florida. 
