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.
Natural Order, Bignoniaceae
Tecoma Radicans, Jussieu
Climbing by stem rootlets, leaves unequally pinnate, leaflets four or five pairs, ovate, acuminate, dentate-serrate, puberulent beneath along the veins; corymbs terminal; corolla tube thrice longer than the calyx; stamens included. (Wood's Class-Book of Botany. See also Gray's Manual of the Botany of the Northern United States, and Chapman's Flora of the Southern United Stales.)
THE Trumpet-flower, Trumpet-vine, or Trumpet-creeper, as it is variously called, is among the best known of our wild flowers. There are but few who have not seen it, and yet how very little is known of the many points of interest it possesses.
In the times just preceding Tournefort, when botany as a system was in a transition state, it was regarded as a sort of Jasmine. Tournefort uses the name of Biguonia, and this was adopted by Linnaeus, in his " Genera Plantarum," from which modern botany dates. A. L. De Jussieu, who, in 1789, issued a Genera Plantarum "according to natural orders," and is regarded as one of the great fathers of the modern natural system, as distinguished from the sexual system of Linnaeus, was the first to separate it from Biguonia, giving it the name of Tecoma; abbreviating, as he tells us, the Mexican name of "Teco-maxochitl," which according to the Spanish writer, Hernandez, is the name given there to some species of the genus. This hard word is really two in the Mexican language, and means " Pitcher-flower," the pitcher being of a peculiar shape, the commentators tell us, and "used in war." But it is now believed that the Aztec "Tecomaxochitl" referred to by Hernandez, is a plant of the Solanum family - Solandra guttata. In botany, however, it is not usual to alter names, though given in mistake; for a name that has no meaning or application is just as good as any other, and it is better to endure these occasional slips in intention, than to increase lists of synonyms.
The botanical difference between Tecoma and Bignonia, as defined by Jussieu, is chiefly in the seed vessel. In Bignonia the valves are parallel with the partition which divides the capsule, while in Tecoma they are contrary to the partition. The natural order receives its name from Bignonia, and in this relation our Trumpet-flower affords an interesting study; and it will show that even what are called natural orders or great families of plants are often divided by what may be regarded as very slender threads. If we compare this flower with some in other allied orders - say, for instance, Mimulus or Pentstemon of the order Scrophulariacece, the student will find numerous points of resemblance. In many flowers we find a coincidence in the number of the floral parts. If, for instance, we find a flower of five sepals, we look for five petals, five (or possibly ten) stamens, and it may be a pistil with five divisions. If there be a less number in any of these series, we look for abortion or consolidation. Bignonia has a five-parted calyx, a five-parted corolla, but we find only four perfect stamens. Theoretical science tells us there should be five, and on looking for this number we can trace it in the flower. We may note the same abortion of parts in some of the Scrophularia, and in Pentstemon the abortive one is so far developed as to suggest the botanical name. Again we find the pistil terminated by two thin lobes, and it is the same in Mimulus, and then, also as in Mimulus, these lobes when expanded close together when touched. Indeed botanists recognize few very important divisions between these two great orders, except that in Bignoniaceca the seed has no albumen, and thus has to send a rootlet at once into the earth on the germination of the seed in quest of food; while in Mimulus the embryo is enclosed in albumen on which the plantlet can feed till full roots are formed.
The reference to the sensitive lobes of the stigma brings before us the question of cross-fertilization by insect agency, to which this sensitiveness in some flowers has been supposed to have some relation. It is believed that an insect, in search of honey, with pollen on its back, would rub against the expanded lobes, which would close before the insect left the flower, thus preventing the reception of its own pollen. In the case of our Trumpet-flower, the lobes close very slowly. In cases observed by the author, they were not completely closed in thirty seconds. The bumble-bee visits the flower only for pollen, so far as the writer can trace. The flower is barely open before the pollen sacs burst, and these are immediately rifled of their contents. The lobes do not expand till after the bees cease their visits, but a portion of the pollen falls on the stigma as the sacs open, and a few grains may find admittance to the stigmatic surfaces through the clefts as the lobes open. Humming-birds enter the flowers for their sweets, occupying from five to ten seconds in each flower. It is possible they may aid in cross-fertilization, but the author has never been able from actual observation to trace just how much, if any, aid may be derived from this source. It is very likely that some phase of nutrition affects productiveness rather than matters connected with pollen from other flowers, for in Pennsylvania we find it is only the flowers which open latest that usually produce seed, as we see in our Fig. 4, where all the early flowers were infertile. In the plants observed by the writer, large numbers of flowers are often seen with the tubular portions split, as in Fig. 3, but by what agency he has never clearly discovered.
Our drawing is from its most northern locality, near Philadelphia, but it is seen in its greatest beauty in the rich alluvial soils along rivers in the Southern States. A lovely sight in a piece of rich woods along the Missouri river, above St. Louis, in which these flowers figured chiefly will ever be remembered. Southwardly from the Gulf of Mexico "------soft gales Stole from a peaceful ocean, whose bright waves Rolled gently into music, and they blew Through woven trellises of all-sweet flowers, And sported round long wreaths of festooned vines Hung with the gayest blossoms,------" and the beautiful tropical scene, as imagined by the poet Percival, seemed more than realized in these magnificent Trumpet-vines, as their wreaths and festoons hung with myriads of gay blossoms, swung at the loftiest heights from tree to tree.
The genus abounds in the tropics, - our species is confined to the southern portion of the United States, reaching the mouth of the Delaware, and going but very little beyond the Mississippi river. In the Pennsylvania locality it is in the height of its beauty about the month of August.
1. Flowering branch.
2. The pistil with its bilobed stigma.
3. Corolla showing the torn tube.
4. Immature capsule, at the end of the rachis, the scars a a showing where the infertile flowers had been.