Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean: Vol. 2, Pt. 4

BOTANY.
PASSIFLORACE2E.
PASSIFLORA INCARNATA, Linn.; Torr. and Gray, Fl. 1. P. 538. Western Texas; May.
GROSSULACE2E.
RIBES AUREUM, Pur8h. Big Springs of the Colorado, &c.; April.
CACTACEA2E.
CEREUIS CSPITOSUS, ECHINOCACTUS TEXENSIS, and OPUNTIA FRUTESCENS, Engelm., occur in the
collection.
UMBELLIFER.E.
AMMIOSELINUM, n. gen. Margin of the calyx obsolete. Petals ovate, entire, nearly plane.
Stylopodium very short, as are the diverging styles. Fruit ovate, laterally compressed. Carpels with five equal, prominent, corky, and scabrous ribs, in the intervals of which there are
single oil-tubes, and two in the commisure. Carpophore 2-parted. Seed straight, semiterete,
slightly concave on the face.-An annual diffuse herb; the leaves decompound with linear ulti
mate segments; flowers in compound umbels, white; leaflets of the involucre and involucels
simple or compound.
AMMOSELIINUM POPEI.-Sandy soil; Llano Estacado, and head-waters of the Colorado; March
and April. Mr. Wright found it in Western Texas, but he collected only a few specimens, and
it was not distributed with his plants. Some ripe seeds that he collected were cultivated in the
Camblridg,e Botanic Garden, and arrived at perfection. Dr. Parry, while engaged on the Mexican boundary survey, under Major Emory, sent home a single flowering specimen of the plant,
found at Eagle Pass in January, 1853. From no other sources have we received any specimens
of this apparently new genus. It grows about a span in length, and though usually diffuse,
some of Captain Pope's specimens must have grown erect, and only a little branched; but they
seem to have been crowded together. The stem and branches are angular, and the angles, a
well as the midribs of the leaves, are rough; in other respects the plant is nearly glabrous.
The leaves are triternally divided, with narrowly linear segments. Umbels compound, or
sometimes decompound. Involuicre of several leaves, which in strong-growing specimens are
large, and resemble the leaves of the stem, being cut into linear segments: the leaves of the involucels are sometimes cut also, but more commonly they are almost entire. Rays of the umbel
seldom more than three or four, unequal: rays of the umbellets 8-10, very unequal. Flowers
very small. Fruit about two and a half lines long and two lines broad, compressed laterally
so that the longer diameter is twice as great as the shorter; the ribs scabrous with little points.
The lateral ones are less prominent, and are confluent with an accessory, thick, corky margin,
which extends through the commissure. We have with reluctance added another genus to the
already extensive family of Umbellifere, already abounding with ill-defined genera, especially
as it is founded on a single species. It is most nearly allied to Chaerophyllum, but differs in
the entire petals, ovate fruit with acute ribs, and shallow furrows of the seed, as well as in the
involuierum.
CYMOPTERUS MONTANUS, Nutt. in Torr. and Gray, FTl. 1, p. 624; Gray, Pt. Fendl. P.'6, and
PI. Wright, 1, p. 79. Eastern part of the Llano Estacado and on the upper Colorado; April.
POLYTENIA NUTTALLII, DC. Prodr. 4, p. 196. On the Colorado, Texas; April. In flower.
DAUCUS PUSILLUS, Mich,. Fl. 1, p. 164. On the Colorado, Texas; April.
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