This section is from the book "The Native Flowers And Ferns Of The United States ", by Thomas Meehan. Also available from Amazon: The Native Flowers and Ferns of the United States in Their Botanical, Horticultural, And Popular Aspects.
Surculosely creeping; leaves oblong-linear, slightly denticulate; pedicel filiform, elongated; petals oblong-ovate; style very short. (Gray, in Proceedings of the American Academy of Arts and Sciences.)
THE plant which we are about to introduce to our readers is one of those which do not attract by showy flowers. Nevertheless, the rich hue of its evergreen leaves gives it a unique character among our native plants, and will make it valuable in the eyes of those who love beautiful foliage, while readers of a more scientific turn of mind will find much of interest in its family history. The genus Pachystima consists of only two species, and was not known until the celebrated expedition made across the continent by Lewis and Clarke in the years 1803-1806, when specimens of one of the species were brought home from the Rocky Mountains by Lewis. Pursh thought it was a holly, and so named it Ilex Myrsinites. Nut-tall, with probably better specimens before him than Pursh, made it out to be a Myginda, which was much nearer the truth, as Myginda is a genus of the order Celastracece, to which our plant belongs. Later, Nuttall himself discovered essential differences between Myginda and the plant originally discovered by Lewis, and established the latter as a new genus, under the name of Oreophila. Rafinesque, however, had already discovered the distinction, and had named the genus Pachystima before Nuttall published his name, and Rafinesque's name, therefore, was generally adopted, in accordance with the ethics of botany, which demand that the name first published with a description showing the distinctive character of the plant to which it is applied shall have precedence.
The derivation of Rafinesque's generic name, Pachystima, is not clear. The pedicel, or flower-stalk, is filiform, as given in Dr. Gray's description, but thickens just beneath the receptacle in both the species belonging to the genus, and if the "thickness," which the name implies, refers to this feature, it would seem to be appropriate. Rafinesque adopted Pursh's specific name for the only species then known, and thus we had Pachy-stima Myrsinites. In Torrey and Gray's "Flora of the United States" it is, however, described under Nuttall's manuscript name of Oreophila myrtifolia, or Myrtle-leaved Mountain-Lover, in allusion both to the character of its foliage and its home in the mountains. This species, the P. Myrsinites, has since been found in many of the mountain localities in the Northwest and in British North America.
The second species, Pachystima Canbyi, was not discovered till 1858, when it was seen by Mr. William M. Canby, of Wilmington, Del., on a bluff along the New River, near White Sulphur Springs, Va.; but it was only in 1868 that Mr. Canby was able to procure good specimens, from which Dr. Gray described and named the plant. Subsequently, our species has been collected in several other places in Virginia by Mr. Howard Shriver, and it is quite likely that it will be found not uncommon along the great Alleghany ridge.
The order Celastraceae, to which Pachystima belongs, is nearly allied to the Rhamnaceae, or buckthorns, but differs from them in several particulars, the most characteristic being that the stamens in the latter are always opposite the petals, provided these are present; while in the former they are alternate with them, as shown in our enlarged flower (Fig. 3), where they are seen fronting the larger sepals, the smaller, oblong-ovate petals lying between. Celastraceae itself is not a very large order, but is, nevertheless, tolerably well known to most persons from the Euonymus, familiarly called the "Spindle-Tree" or "Burning-Bush." The order is again divided into two general sections, the one to which the Euonymus belongs having rather dry capsule, opening to let out the somewhat fleshy seed; while the other, in which our Pachystima is placed, has drupa-cious fruit, or in plain English, a kind of fruit which resembles stone-fruit. With the easily obtained Euonymus before him, the student can readily gain a fair idea of the two divisions of the order. The berries on our species, however, seem to be sparingly produced, and the only ones we ever saw were in a dry condition on Mr. Canby's specimens. Although the plant from which the accompanying plate was drawn has flowered freely in cultivation for several years, it has never produced any fruit; but as in the case of-the flowers themselves, it is not likely that the berries would add much beauty to our pretty evergreen plant.
The fact just alluded to, that the Pachystima Canbyi produces berries but sparingly, opens up a question which was already discussed by the botanists of the preceding generation, in connection with the sister species, P. Myrsinitcs. The question is, whether the plant may not prove to be, in many cases, monoecious, or even, practically at least, dioecious. Nuttall believed P. Myrsinites to be monoecious, or having the male organs in one set of flowers, and the female organs in another. Torrey and Gray, on the contrary, thought it must be hermaphrodite, or with both kinds of organs in each flower, more especially so as Sir William Hooker had figured it that way. But modern experience shows us that even when both kinds of organs are apparently perfect, the one or the other may be defective, and hence the plant may be practically monoecious, or indeed even dioecious, if it should so happen that on some individuals all the male organs are defective, and on others all the female organs. The flowers on our plant seem perfect, but, as already stated, produce no fruit.
The plant increases by branches running under the ground, and rooting, if the soil be light, or by sending out roots from branches that find themselves near the ground, or covered by-loose vegetable matter. The early spring-shoots have the leaves very variable in form, from linear to ovate, and much more sharply denticulate than those which appear on a second growth of branches, sent out later in the season. It is on these later branches that the flowers appear in the following spring.
To cultivators the plant will prove very acceptable as an evergreen dwarf bush. In the writer's garden it has a frame, a shallow, bottomless box, a few inches deep, placed around it, filled with sand, into which it seems to love to root. The rooted pieces are easily transplanted to form other colonies. Little pieces of cuttings also root very well in pans of sand, set in an ordinarv green-house.
The fact that a distinct genus like Pachystima should have only two representatives, and these confined to limited areas over this great continent, will be a subject of speculation with those interested in the genesis of plant-forms. Are these species new forms, which have appeared comparatively quite recently, and which by and by will become more numerous by developing into varieties and other species, or are they very old forms, now in process of extinction? The time may come when there will be circumstantial evidence sufficient to answer these questions, and the earnest attention which they command among scientific men at the present time springs from the belief that it will eventually be possible to answer them satisfactorily.
Our plant has absolutely no common name, and by way of rectifying this omission we have ventured to call it "Canby's Mountain-Lover," for reasons which must have become apparent to the reader in the course of this article.
1. Main branch, with secondary branches, showing the denticulation of the leaves.
2. Branchlet of the second growth, with entire leaves, in flower in spring.
3. Flower magnified, showing the position of the anthers, and the symmetrical arrangement of all the parts.