133 
+ + Flowers scarlet, open day and night, 
11. ©. phceniceus Eng. Globose or oval obtuse heads 5 to 7.5 em. high, cespitose 
(several to over 100 from same base, often forming dense hemispherical masses) : 
ribs 8 to 11: areolie ovate to orbicular: spines slender and straight, the radials 8 to 
12, white, 6 to 24 mm. long, the upper a little shorter than the rest; central ones 1 
to 3, bulbous at base, terete, a little stouter, 10 to 30 mm. long: flowers deep red, 3.5 
to 6.5 cm. long and half as wide. (C. Remeri Eng.)—In the granitic regions of west- 
ern Texas, from the Llano westward. 
12. C. conoideus Eng. Ovate-conical acutish heads, 7.5 to 10 cm. high, few of 
unequal height from a common base: ribs 9 to 11: radial spines 10 to 12, slender and 
rigid, upper ones 4 to 10 mm, long, laterals 12 to 30 mm.; central ones 3 to 5, the 
upper hardly longer than the radials, the lowest one 4-angled and often compressed, 
2.5 to 7.5 em. long, at length deflexed.—Rocky places along the upper Pecos and 
probably within the Texan boundary. 
13. C. polyacanthus Eng. Ovate-cylindrical, cespitose, 12.5 to 25 cm. high, 6.5 
to 10 cm. in diameter: ribs 9 to 13: spines stout, rigid, straight, white or ashy-red, 
upper radials 12 mm. long, lateral and lower ones 18 to 24 mm. ; central spines 3 or 
4, hardly longer, or the lower sometimes 3.5 to 6.5 em. long, a little stouter ; younger 
ones often variegated grayish-brown: flowers 5 to 7.5 em. long, profusely covering 
the plant.—Common about El Paso. 
14. C. paucispinus Eng. Ovate-cylindrical, sparingly branching or simple, 12.5 
to 22.5 em. high, 5 to 7.5 cm. in diameter: ribs 5 to 7: areole remote: 3 to 6 stout 
radiating dark-colored spines, 18 to 32 mm. long, the central one almost always want- 
ing or rarely a stout subangled one 30 to 40 mm. long.—From the San Pedro to the 
mouth of the Pecos. 
*** Low and spreading usually articulated plants, with cylindrical simple or very branch- 
ing stems and few short or even minute slender spines. 
15. C. Berlandieri Eng. Low and very green, the stems diffuse, subterete, articu- 
lated and very branching, 3.5 to 15 em. long and 2.5 em. thick: tubercles conical: 
spines 6 to 8, slender, short, the radials white and 8 to 10 mm. long, the single cen- 
tral one grayish-brown, much longer (12 to 24 mm.): flowers 5 to 10 em. long, with 
narrow recurved petals: seeds tuberculate.—On the Nueces. 
16. C. procumbens Eng. Similar to the last, but stems more slender and 4 or 5- 
angled: spines 4 to 6, the radials white, 2 to 4 mm. long, central one, if present, 
dark and 4 to 6 mm. long: flowers over 7.5 cm. long. with obovate-spatulate spread- 
ing or somewhat recurved petals: seeds very delicately warty.—On the Rio Grande 
near and below Matamoras. 
17, C. tuberosus Poselger. Very slender from a tuberous root, terete, thickened 
upward, at length articulated: ribs 8: spines minute and slender, the 9 to 12 radial 
ones hardly 2 mm. long, the solitary central one longer (4 to 6 mm.) and appressed 
upwards: flowers subterminal.—On the lower Rio Grande, 
§ 2. Stem elongated, prismatic or cylindric, mostly branching, with longer flowers and 
whitish stigmas: seeds obovate, usually smooth or pitted. 
18. C. princeps Hort. Wiirzb. Erect, 3 or 4-angled, 9 to 30 dm. high, 5 em. in dia- 
meter: areole remote: radial spines 4 to 6, short; 2 to 4 interior ones stout, elon- 
gated, unequal, divaricate, central one deflexed ; larger spines 24 to 36 mm. long: 
flowers large, white, nocturnal : berry scarlet, 5 to 7.5 em. long, spiny. (C. variabilis 
Pfeiff.)—On the lower Rio Grande. 
19. C. Greggii Eng. Slender, erect from a large fleshy napiform root, 6 to 9 dm. 
high, 18 to 24 mm. thick: branches 3 to 6-angled, reddish: areola crowded: spines 
abruptly subulate from a bulbous base, very short (1 to 2 mm. long), blackish ; radials 
6 to 9; centrals 1 or 2: flowers elongated, 15 to 20 em. long, 5 to 6.5 cm. wide, the 
white tube armed with capillary flexuous spines: berry sessile, obovate, beaked, 2.5 
to 3.5 cm, long.—From the San Pedro westward and southward. 
