162 UNITED STATES AND MEXICAN BOUNDARY. 
SARCOSTEMMA HETEROPHYLLUM; var.? umbellis 5-8-floris, pedicellis pedunculo subzequalibus; 
floribus majoribus; corolle laciniis oblongis obtusis. Gravelly hills, Rock Creek, and near 
Camp Bache, also at the mouth of the Great Cañon of the Rio Grande, June—July. (No. 1679, 
Wright.) Perhaps distinct from S. heterophyllum: we have seen no intermediate forms. The 
leaves are usually longer and wider; the flowers are of a dull purple color, and the segments of 
the corolla are more strongly ciliate. Gynostegium distinctly stipitate. Follicles 4 inches long, 
acute at the base, and tapering to a long point. 
ASCLEPIAS SULLIVANTII, Engelm. in Gray’s Manual, ed. 2, p. 352. Hill.sides, Muerte and Rock 
Creek ; also at the Copper Mines, July—August; Bigelow. "The pods are sometimes almost 
entirely free from warts or spines. Leaves often very obtuse, or even emarginate. 
Аестерілв JAMESII (n. sp.): glaberrima, subglauca; foliis orbiculato-obovatis subcoriaceis 
retusis vel emarginatis basi cordatis brevissime petiolatis; umbellis multifloris brevi-peduncu- 
latis ; gynostegio constricto ; cucullis dilatatis truncatis ; processu arcuato falciformi acutissimo 
exserto; folliculis ovatis levibus. A. obtusifolia var.? latifolia, Torr. in Ann. Гус. 2, p. 117. 
Plains near the Limpio Mountains, July; Bigelow. Tascate, Sonora, July; Parry. (No. 1682, 
Wright.) Stem stout, 1-2 feet high. Leaves 8—4 inches long, and 23-33 wide, somewhat 
coriaceous, transversely and reticulately veined, mostly retuse or emarginate, with a small 
abrupt point; the lower ones almost orbicular ; petiole 1-3 lines long. Umbels several, in the 
axils of the upper leaves. Peduncles 2—4 їнэ long. Flowers much resembling those of A. 
Sullivantii, Corolla greenish; segments broadly ovate. Hoods of the crown purplish, very 
broad, obliquely truncated, the horn with the acute point exserted and projected partly over 
the stigma, tne upper margin undulately 2-3-toothed. Horny margins of the anthers angularly 
dilated at the base. This species was first discovered by Dr. James, on Long's Expedition to 
the Rocky Mountains, and was doubtfully regarded as a variety of A. obtusa in my account of 
the plants collected by that botanist. It was afterwards found by Lieut. Abert, as well as by 
Fendler, in New Mexico. M? 772, ‚ 
ASCLEPIAS EROSA (n. sp.): puberula deinde glabrata; caule erecto simplici; foliis oblongo-ovatis 
subcoriaceis acuminatis sessilibus margine eroso-denticulatis ; umbellis multifloris ; pendunculis 
folio duplo brevioribus; cucullis obovatis obtusis\ dio din ibus ^g; ynostegio constricto); processu 
subulato arcuato longe horizontaliter exserto ; folliculis ov ovatis, acuminatis levibus.—Valley 
of the Gila river, near Metate, May—June; Schott, Thurber. Stem apparently 2-3 feet high, 
stout. Lower leaves 5-7 inches long, and 23 broad, with a long acute point, very rough on the 
margin, with irregular conspicuous .cartilaginous serratures. Umbels 5 to 7, about half as long 
as the leaves ; pedicels 14 inch long, pubescent, Flowers as large as in А. Cornuti. Corolla 
greenish white; segments at length reflexed. Hoods of the crown obliquely truncate at the 
summit, the subulate horn exserted horizontally. Pods (immature) about 2 inches long, and 
nearly an inch in diameter at the middle.—Apparently allied to A. glaucescens, Н. B. & E. 
but that species has obtuse leaves, much shorter pedicels, and a subsessile gynostegium, which 
is about the length of the hoods. 
ASCLEPIAS ARENARIA (n. sp.): incano-pubescens, deinde glabrescens; caule simplici; foliis 
oppositis obovatis vel inferioribus ovatis breviter petiolatis, superioribus emarginatis vcl retusis ; 
 peduneulis brevibus multifloris, cucullis dilatatis obtusissimis utrinque unidentatis gynostegio 
subsessili longioribus, processu subulato apice subrecurvo ; folliculis oblongis attenuatis 
levibus.—Sandy banks ; Journado del Muerte, and on the upper Rio Grande, in New Mexico, 
June—July. Plant 12—18 inches high, (apparently sometimes assurgent or prostrate.) Leaves 
