There are four official reports on the Botany of the United States Expeditions for the purpose of surveying a railroad route from the Mississippi River to the Pacific Ocean, prepared by order of the American Government, by Drs. Torrey and Asa Gray. The four form a thin 4to volume with 35 excellent plates engraved on stone by Mr. Sprague. These publications do honor alike to science and art, and are worthy rivals of the best of the works of a similar nature published under the direction of European governments. From among the new or rare plants observed in these expeditions we notice several, the introduction of which to our gardens would be highly desirable.

The first expedition under Lieut. Beckwith, who, taking with him Mr. James Snyder as collector, proceeded from the Great Salt Lake in Utah, directly west to the Sacramento valley, in California, seems to have passed through a country yielding little novelty; new species of Viola, Astragalus, CEnothera, Phlox, Phacelia, Pentstemon, Calochortus, and Brodiaea, none of much mark, forming the principal acquisitions. The second expedition, under Capt. Gunnison, accompanied by Mr. Creutzfeldt, was better rewarded; this took a course from Fort Leavenworth, by way of the Kansas and Arkansas rivers into the great basin of Utah, and thence to the neighborhood of Lake Sevier or Nicollet. Several new species were found; among old ones the most important were Abies taxifolia, a handsome tree growing from 35 to 40 feet high and 12 to 16 feet in diameter, and an undetermined Pinus without cones, apparently between fiexilis and Strobus on the highest places in the Cochetopa; the leaves grow in fives, and were smeared with a clear, colorless balsam. The third expedition under Captain Pope was not more successful; although its route was 6° or 7° more to the southward, near the 32d parallel of latitude.

Little horticultural occurred on this line except Pentstemon Fendleri, a species with blue or purple flowers, near P. acumina-tus. The last expedition under Lieutenant Whipple, accompanied by Dr. J. M. Bigelow, passed over very fine collecting ground, especially through western New Mexico between 35° and 36° north latitude to the great Colorado River, passing by the valley of Williams' River, commonly called Bill Williams' Fork, one of the tributaries of the great stream. This district is spoken of as a country very rich and peculiar in its flora. A number of new genera and above 60 new species rewarded the exertions of the exploring party. Among the more important acquisitions were the following: - 1 Fremontia Californica; this rare and beautiful shrub, was found 15 feet high in the Cajou pass of the Sierra Nevada. 2 Spircea Millefolium, a low shrub with the leaves of a Milfoil. 3 Pentstemon spectabilis, from the San Francisco mountains in New Mexico and elsewhere, with a crowded panicle of purplish blue flowers, often 2 feet in length. 4 Quercus erinacea, a fine Oak with bristly cups and large Chestnut-like leaves, growing 25 to 30 feet high on the Californian mountains. 5 Taxus brevifolia; this, the northwestern Yew, Dr. Torrey considers distinct from that of Europe. 6 Washing-tonia gigantea, which Dr. Torrey, following Decaisne, regards as a species of Sequoia. 7 Pinus Engelmanni (a name proposed instead of that of P. brachyptera) said to be a very fine species, with leaves sometimes nearly 6 inches in length, common on mountain ranges between the Pecos and Rio Grande quite to the Sierra Nevada; it is called Yellow Pine and Pitch Pine in some places. 8 Pinus flexilis; this is said to resemble greatly P. Cembra; its ordinary height is from 40 to 50 feet, but Dr. Bigelow saw trunks more than 100 feet high.

The seeds are eatable. 9 Juniperus tetragona? the smooth barked Juniper, of Bill Williams' Mountain, and on hills west of the Colorado, seems to be distinct from the Mexican plant of the same name, having much larger fruit. Dr. Torrey calls it a variety named osteospermcu 10 J. pachyphloea^Tom the Zuni Mountains, in West Mexico, the thick barked Juniper of Sitgreaves, has sweet berries, like the last, which are said to be used by the Indians as food.