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.
Scape tumid at the base, five to seven flowered; leaves two, linear-lanceolate, abruptly pointed; bracts short, ovate; sepals and petals spatulate-lanceo-late, acute; lip three-parted, two-crested in the middle; the lateral lobes oblong, acute; the middle one wedge-shaped, notched at the apex; the claw partly adnate to the two-winged column. Scape about one foot high, invested with numerous short whitish sheaths. Leaves four to five inches long. Flowers eight lines long. (Chapman's Flora of the Southern United States.)
WHEN William Bartram made his journey to Florida in the interest of Peter Collinson, he discovered an orchid growing on the Magnolia grandiflora, and which is now known as Epidendrum conopseum; and, for a long time afterwards, this was regarded as the only orchidal epiphyte - that is to say, an orchid growing on trees - in the United States. But during comparatively recent years a second epiphyte has been discovered in Florida, and of the same genus as the other. The first knowledge the writer had of it was from some specimens sent to him from Florida, soon after the Secession war, by Mr. Wm. M. Canby, of Wilmington, Del. These were fastened to a block of wood with a little moss tucked in about them, when they grew well, and bloomed the following year. The first description of it in an American work appears in Chapman's "Flora of the Southern United States" of 1872, as quoted at the head of our chapter, where its discovery in Florida is credited to Dr. Blod-gett. It appears, however, to be frequently met with by collectors in Florida, since its existence there was first made known. In the " Bulletin of the Torrey Botanical Club," Volume 6, Mary C. Reynolds writes of the beautiful appearance it presents when growing on magnolias in that State; and in the first volume of the "Botanical Gazette," Mr. A. P. Garber, referring to the plants of Florida which attracted his attention when he first visited Eastern Florida in February, notes among his particular impressions this singular orchid then in fruit.
Though found so recently in the United States it is not a new species, for it was discovered in Mexico by Theodore Hartweg, who was sent to that country about the year 1836 and 1837 by the Royal Horticultural Society of London, to collect seeds and roots of the most beautiful plants he could find there for cultivation in English gardens. Hartweg says he found it growing on oak trees. In Florida it is reported as chiefly on magnolias; but it is worth noting that these plants are not parasites, deriving their sustenance from the living trees, but are only supported on the branches, obtaining their chief nutrition through their aerial roots, with perhaps a little aid from the dead bark of the supporting tree. When, therefore, we find the same species of orchid seeming to prefer one class of tree in one country as the oak in Mexico, and the magnolia in Florida, the reason is to be sought in the varying conditions of climate as regards light, shade and moisture. The seeds of our tree orchis, as indeed of all orchideous plants, are as fine as dust, and require nicely balanced conditions to germinate. There must be just so much moisture, just so much heat, and just so much shade, and these requirements vary in many species. In some countries, and for our species for instance, these exact conditions would be better secured on the branch of a magnolia than on an oak, while in others the oak would furnish them to better advantage. It is also worthy of note in connection with orchid seed that the conditions most favorable to germination are not those generally the best for the growth and subsequent flowering of the orchid plant, and these observations lead to some remarkable teleo-logical conclusions. The little dust-like seeds, floating in the air till caught by some branch, would not germinate if the branch were exposed to the full sunlight, and would be liable to be dried completely a few hours after a shower of rain. It is therefore only when there is continuous dampness and shade on the branch that the seed can grow; and this is of course best secured in the deep recesses of the forest, or on some peculiar class of trees, which at the germinating season of the year offers the best of these crowing conditions. But though shade and gloom be necessary for germinating, the growing plant loves sunlight and a dryer air. The growth therefore is weak, and the flowers few in their usual place of growth; but if a tree, covered with plants, finds itself eventually exposed to full sunlight, the plants assume great vigor, and flower in profusion. We have in these cases a very valuable lesson as to the working of nature. She evidently cares far more for the welfare of the race than of the individual, for she makes the individual to grow in places not the most favorable for individual development, because the race is thus the better preserved. The individual plant therefore has very little power of selection. It has to do as it must rather than as it likes, and it is a great gain to the student of nature to clearly perceive this law.
We may regard it as a piece of good fortune that this beautiful species has wandered up through the ages from Mexico to our territory, so that we can include it among the illustrations of the native flowers of the United States. For it will give us a faint idea of the great beauty of tropical forests in which epiphytal orchids are exceedingly numerous, and far excel in gorgeous-ness the species illustrated here. The chief variations generally are in the form and markings of the lip, as what we might style the sixth petal in an orchid flower is called. Most students know that an extensive type of flower is that which has three leaves called sepals in one whorl making the calyx, and then three more making the inside set of petals or the corolla; but even these whorls are formed in a line, spiral though it be. The three divisions in each whorl are not formed together, but one alter another, and thus in the whole six there are a first and a last. If we look at this orchid flower we see that if the lip had been made like the other divisions, we should have had a six-parted corolla of a very common type, and in making orchid flowers nature has done little more than busied herself in seeing how different she could make the lip from the other five divisions of the six-parted flower. In the present case the lip is not much different from the other divisions. It is a little broader, but depends chiefly for its distinctiveness on its incurved base. The beautiful rose-colored veins give it its chief attraction, and it is from this that it derives its specific name venosum, which is Latin for veined.
Our description tells us that the plant is "tumid at the base." These bases are known to gardeners as pseudo-bulbs, that is to say, "false" bulbs; but really there is no difference in their essential nature from true bulbs. They are both formed from the thickened and united bases of the leaves, but the true bulb is generally formed under ground. New pseudo-bulbs are formed every year as the root stock grows. At Fig. 1 we see the remains of the pseudo-bulbs of years gone by, which have had leaves, and probably flowers. At Fig. 3 we have the more recent ones, which in a few years will look as Fig. 1. From these new bulbs, the new roots, Fig. 2, come, and by which they feed and are attached to the supporting tree. The roots always come out from the new bulb. After the leaves have been fully formed, roots will never come out again from the bulb that bears them.
1. Old pseudo-bulbs, at what was once the termination of the root stock.
2. New bulbs at present terminus of the creeping root stock.
3. Aerial root.
4. Complete plant, full size, in flower.
5. Branch of tree on which it is growing in Cambridge Botanical Garden.