160 UNITED STATES AND MEXICAN BOUNDARY. 
beak, which is somewhat longer than the erect anther-membrane. Pods not seen. We refer 
this plant to Metastelma with much doubt, but there is no other genus to which it seems to be 
more allied. It occurs also in Lindheimer’s Texan Collection. 
ROULINIA UNIFARIA, Engelm. MSS. Gonolobus unifarius, Scheele in Linnea, 21, p. 760. Shady 
thickets, near the Rio Grande, western Texas and New Mexico, July—October ; Schott, Bige- 
low. (Nos. 546 and 1672, Wright.) I fear that itis too near R. Jacquini. 
ACERATES VIRIDIFLORA, Ell. Sk. 1, p. 317; Decaisne in DC. Prodr. 8, p. 522. Asclepias 1 
` viridiflora, Pursh, Fl. 1, p. 181. Western Texas; Bigelow. No. 1693, Wright, is a variety | 
with broadly obovate and emarginate leaves. In my Flora of the Northern and Middle States 
(2, p. 182) I incorrectly referred Asclepias obovata, Wil., to this variety ; a mistake which has 
been copied by Decaisne. Elliott’s plant is a genuine Asclepias; but A. obtusifolia 8, Torr., 
also referred by Decaisne to A. obovata, is our A. Jamesii, described below. 
ACERATES DECUMBENS, Decaisne, l. c. Anantherix decumbens, Nutt. l. c. p. 202. Valley of 
the upper Rio Grande and westward to the Gila river, April—August. 
Ж ACERATES AURICULATA (Engelm. MSS.): ‘caule erecto glabro; foliis sparsis linearibus filifor- 
mibus ; umbellis pluribus axillaribus multiflorus breviter pedunculatis ; pedicellis pilosis, calyce 
extus villoso; corolle laciniis reflexis ; cucullis gynostegio globoso sessili brevioribus apice 
leviter tridentatis margine involutis basi latissime biauriculatis; folliculis lanceolatis longe 
rostratis brevibus." Dry ravines near the Copper Mines, and along the Mimbres, June—July ; 
Bigelow. Stem 2-3 feet high, somewhat glaucous. Leaves slightly scabrous on the margin, 
which is not revolute, 4—6 inches long, j-j line (rarely as much as а line) wide.  Pedicels 6 
lines long. Lobes of the corolla 24 lines long. Horny wings of the anthers rounded, not 
angular as in most Asclepiadeæ. 了 ollen-masses also, of an unusual shape, curved, nearly 
equally wide, and obtuse at each end: remarkable, also, for the large triangular wings at the 
sides of the hoods. Pods 3 or 4 inches long. Resembling A. angustifolia, but easily dis- 
tinguished by the perfectly smooth stem and non-revolute leaves, but especially by the larger 
flower, the peculiar structure of the cuculli, and the shape of the pollen-masses. This is No. 
106 of Fendler's New Mexican Collection, and No. 1687 of Wright's. It was found also by 
Frémont on the upper Arkansas. Doubtless it has often been confounded with A. angustifolia. 
ACERATES (ANANTHERIX) TOMENTOSA (n. sp.): albo-lanata; caule erecto simplici; foliis ovatis 
acutis sessilibus basi rotundatis v. cordato-amplexicaulibus; umbellis sessilibus plurifloris; 
gynostegio sessili; cucullis suborbicularis saccatis apertis lateraliter compressis. (ТАВ. XLIV ) 
Mountains east of San Diego, California, June; Parry. San Isabel, in the same State; Thurber. 
We have also specimens collected by the Rev. Mr. Fitch, in some part of California. Stem 2-3 
feet high. Lower leaves 4—5 inches long, and nearly 3 inches wide, usually clasping at the 
base. Umbels 3-4, in the axils of the upper leaves, 8-12-flowered; pedicels 1-13 inch long, 
very densely clothed with white wool. Flowers a third larger than in Asclepias Cornuti, ** of 
a chocolate-purple color." (Parry.) Petals ovate, reflexed, woolly externally. Hoods of the 
crown nearly orbicular, spreading, without any trace of a spur, the margin of the orifice entire 
and introflexed. The horny wings of the anthers almost rectangular at the base. Follicles 
oblong-lanceolate, downy. This is a remarkable species, belonging rather to the subgenus 
Anantherix than to Acerates proper. 58 
SARCoSTEMMA BILOBUM, Hook. & Arn. Bot. Beechey, р. ا‎ 8. cynanchoides, Decaisne, 5 6; : 
p.540. S. Texanum, Engelm. MSS. Gonolobus cynanchoides, Engelm. & Отау Pl. Lindh. 1, 3 
7 р. 43. Borders of the Rio Grande, from Presidio del Norte to Eagle Pass, June—October ; : 
