OF ARTS AND SCIENCES. 299 
aments sessile or nearly so, of 4 to 6 pairs of connate bracts: fila- 
ments long-exserted, united throughout or the anthers (4 to 8) shortly 
stipitate: fertile flowers upon a scaly-bracted (rarely naked) peduncle 
1 to 6 lines long; bracts 4 or 5 pairs, round-ovate, connate: fruit 
solitary or in pairs, 5 or rarely 4 lines long, exserted, acutish, smooth ; 
micropyle a line long. — #. antisyphilitica, Watson, Bot. King. Exp. 
328, t. 89. Throughout the interior from N. Nevada to the Colorado 
Desert (Fort Mohave, Cooper), Northern Mexico (Gregg), and the 
Rio Grande. The New Mexican form has more usually very short 
peduncles and solitary fruit. Californian specimens collected at Fort 
Tejon (a. 112, Xantus) and in the Santa Inez Mountains (n. 347, 
Brewer), without flowers or fruit, are peculiar in having persistent 
scales and may possibly prove distinct. 
Erepra’t Torreyana. Erect, 1 to 3 feet high or more, the 
branches often somewhat flexuous, not spinose, usually ternate: scales 
short (a line or two long), sheathing, ternate, with broad and acutish 
or rarely narrow lobes, subpersistent, not becoming shreddy : staminate 
1 The North American species of this genus may be defined as follows : — 
* Scales 2-lobed and the branches (not spinose) opposite: bracts in pairs and evidently connate, 
scareely at all scarious: fruit solitary or in pairs, smooth, 
1. E. antisypuititica, C. A. Meyer. Stems mostly lax and slender, decli- 
nate and nearly prostrate or supported on shrubs or trees to a height of 8 or 10 
feet ; bark not shreddy nor fibrous: scales distinct, subpersistent, very short and 
triangular-ovate, or when young setaceously tipped and slightly sheathing (some- 
times 2 lines long): aments on short bracteate peduncles: filaments distinct 
above the perianth: fertile flowers with 3 or 4 pairs of bracts: fruit 24 or 3 
lines long: otherwise as the next, but micropyle slightly shorter. — W. Texas 
and New Mexico (n. 820, 1590, Berlandier; n. 675, 1881, Wright; n. 225, 273, 
428, Lindheimer), to Northern Mexico (n. 855, Parry & Palmer, 1878). 
2. E. Nevapensis, Watson. See above. 
* * Scales ternate and branches mostly in threes: bracts ternate, distinct or slightly connate, 
those of the fertile flowers more or less conspicuously scarious and unguiculate: fruit solitary 
or in threes. 
3. E. rrirurcA, Torr. Erect, much branched, 2 to 6 feet high, the straight 
rigid branches spinosely tipped: scales conspicuous, sheathing, 3 to 6 lines long, 
sharply acuminate, persistent, becoming whitish and shreddy : staminate aments 
on a very short peduncle, of 5 whorls of ovate bracts about equalling the 
cuneate-oblong perianths: anthers (4 or 5) stipitate: fertile flowers nearly 
sessile, 5 or 6 lines long, of numerous whorls (8 to 10) of very thin and scarious 
entire round-cordate unguiculate bracts: fruit solitary, 6 lines long, 4-sided, 
attenuate upward, smooth: micropyle 23 lines long. — Arizona and New 
Mexico; Mohave Agency, Dr. E. Palmer (n. 5234, 1876) ; near El Paso, Dr. 
Bigelow ; near Fronteras, Wright (n. 1884). 
4, E. Torreyana, Watson; and 5. E. Catirornica, Watson. See above. 
