388 
appressed, 3 to 5 upper setaceous, short (2 to 4 mm.), white, lateral 
elongated (14 to 18 min.), recurved and reddish, lower 8 mm. long; cen- 
tral solitary, much stouter, reddish and porrect, 2.5 em. long: flowers 
red, with tube over 5 em. long: fruit unknown.—Type, Wislizenus of 
1846 in Herb. Mo. Bot. Gard. 
In the mountains of Chihuahua, “ Cosihuiriachi, mountains west of 
Chihuahua.” 
Specimens examined: CHIHUAHUA ( Wislizenus of 1846), 
17. Cereus longisetus Engelm. Syn. Cact. 280 (1856). 
Ovate-cylindrical, subsimple, 15 to 22.5 em. long and 5 to 7.5 em, in 
diameter: ribs 11 to 14, distinctly tuberculate: spines setaceous, white, 
flexible and spreading; radials 18 to 20, straight, lower (10 to 14 mm. 
long) much longer than the upper (5 to 6 mm.) which are also more 
slender; centrals 5 to 7, the upper hardly longer than the radials, the 3 
lower elongated (2.5 to 5.5 cm.), divaricate, often flexuose and deflexed: 
flowers said to be red: fruit unknown, (JU. Cact. Mex. Bound. t. 45)— 
Type, Bigelow of 1853 in Herb. Mo. Bot. Gard. 
Coahuila, “Santa Rosa, south of the Rio Grande.” 
Specimens examined: COAHUILA (Bigelow of 1853), 
** Stems oval: ribs fewer (5 to 13); spines few (3 to 12), longer, not pectinate. 
+ Flowers purple (yellow in tlaviflorus). 
++ Central spines usually 3 or 4, 
18. Cereus engelmanni Parry, Amer. Jour, Sci. ser. 2, xiv, 338 (1852). 
Ovate-cylindrical, 12.5 to 30 em. high (sometimes reaching 45 em.), 5 
to 7.5 em. in diameter, simple or sparingly branched at base, loosely 
cespitose (4 to 8 stems together): ribs 10 to 13, tuberculate, with areole 
4 to 8mm. apart: radial spines 12 to 14 (usually 13), slender, 6 to 12 
mm. long, white with dark tip, upper (about 4) setaceous and much 
shorter, lateral (6) and lower (3) longer and stouter, straight or a little 
incurved; centrals 4 (rarely 5), straight and angled, 2.5 to 5 em. long, 
cruciate, the 8 upper yellow and erect, the lower one white, porrect or 
detlexed: flowers purple, 5 to 7.5 cm. long: fruit ovate, fleshy, spiny (at 
length naked), 4 em. long, 2.5 em. in diameter: seed obliquely obovate, 
black and tuberculate, 1.2 to 1.4 mm. long. (JU. Cact. Mex. Bound. 
t. 57) —Type, Parry of 1850 in Herb. Mo. Bot. Gard. 
From Salt Lake Desert, Utah, westward to the eastern slopes of the 
California Sierras, and southward into Sonora, and Lower California; 
also on Cedros Island. 
Specimens examined: NEVADA (Shockley 313): ARIZONA (Bischoff of 
1871; Mrs. Thompson of 1872; Coues & Palmer 303; Palmer of 1878): 
CALIFORNIA (Parry of 1850, “Mountains about San Felipe;” Palmer 
of 1870 and 1876; Lemmon of 1878; Hngelmann of 1880; Parish Bros. 
165 of 1882, San Diego Co.): LowmR CALIFORNIA (Gabb 14 of 1867; 
