Page:Memoir of a tour to northern Mexico.djvu/87

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Dr. Wislizenus has intrusted to me his very interesting botanical collections, with the desire that I should describe the numerous novelties included in them. Gladly would I have done so, had not leisure been wanting, and were I not here (in St. Louis) cut off from large collections and libraries. As it is, I can only give a general view of the flora of the regions traversed, and describe a few of the most interesting new plants collected; with the apprehension, however, that some of them may have been published already from other sources, without my being aware of it.

In examining the collections of Dr. Wislizenus, I have been materially aided by having it in my power to compare the plants which Dr. Josiah Gregg, the author of that interesting work "the Commerce of the Prairies," has gathered between Chihuahua and the mouth of the Rio Grande, but particularly about Monterey and Saltillo, and a share of which, with great liberality, he has communicated to me. His and Dr. W.'s collections together, form a very fine herbarium for those regions.

The tour of Dr. Wislizenus encompassed, as it were, the valley of the Rio Grande and the whole of Texas, as a glance at the map will show. His plants partake, therefore, of the character of the floras of the widely different countries which are separated by this valley. Indeed, the flora of the valley of the Rio Grande connects the United States, the Californian, the Mexican, and the Texan floras, including species or genera, or families, peculiar to each of these countries.

The northeastern portion of the route traverses the large western prairies, rising gradually from about 1,000 feet above the gulf of Mexico, near Independence, Missouri, to 4,000 feet west of the Cimarron river. The plants collected on the first part of this section, as far west as the crossings of the Arkansas river, are those well known as the inhabitants of our western plains. I mention among others, as peculiarly interesting to the botanist, or distinguished by giving a character to the landscape, in the order in which they were collected, Tradescantia virginica, Phlox aristata, Oenothera missouriensis, serrulata, speciosa, &c., Pentstemon Cobaea, Astragalus caryocarpus, (common as far west as Santa Fe,) Delphinium azureum, Baptisia australis, Malva Papaver, Schrankia uncinata and angustata, Echinacea angustifolia, Aplopappus spinulosis, Gaura coccinea, Sida coccinea, Sophora sericea, Sesleria dactyloides, Hordeum pusillum, Engelmannia pinnatifida, Pyrrhopappus grandiflorus, Gaillardia pulchella Argemone Mexicana, (with very hispid stem and large white flowers.)

The plants collected between the Arkansas and Cimarron rivers are rarer, some of them known to us only through Dr. James, who accompanied Long's expedition to those regions in 1820. We find here Cosmidium gracile, Torr. and Gr., which has also been collected about Santa Fe and farther down the Rio Grande; ''Cacumis? perennis,'' James, found