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.
Annual, clammy-pubescent; leaves thin, opposite, ovate, lanceolate, long petioled, rough ; flowers nearly sessile, borne between the petioles, solitary ; petals violet-purple; stamens 12. (Chapman's Flora of the Southern States, See also Gray's Manual and Wood's Class-Book of Botany.)
HIS plant, known by the common name of " Blue Wax-Weed," is not particularly showy, but is sure to attract the collector by its singular structure. The flower has six petals inserted on the calyx, but four of them are mere narrow threads, leaving to the two upper ones the support of all the reputation for beauty the little flower may possess. We are often tempted to believe that the color of a flower is for the purpose of attracting insects. It may be so, and there are many botanists who accept this as the true explanation of the motive for color. Yet it would seem that our plant would have been better served in this respect if all the six petals were of equal prominence in size and color; and it is more than likely, if flowers be really intended to attract insects, and if, as some botanists further contend, certain special flowers are even specially designed to attract special insects, that form is quite as important as color in this respect, and that the variety of form as well as the origin of color may be due to the same cause.
The calyx and stems are somewhat colored, and so help to make the plant attractive. There is a slight swelling on the upper side of the calyx at the base, which gives it a gibbous appearance, and this suggested the botanical name, Cuphca, which is derived from a Greek word signifying "curved." The common crape myrtle of our gardens, which belongs to the same natural order of Lythracea, may give some general idea of the family relations, while the well-known cigar flower, Cuphea platycentra, will afford ready means of comparison.
The plant is a most interesting one to study, as showing how very little differences in structure will lead to great diversity in organization. One would not at first sight suppose there was any very close relationship between Cuphea viscosissima and the common garden Fuchsia, and when the student turns to his text-book of botanical classification he finds them widely separated. But there is really little difference essentially. The calyx in Cuphea, as seen in our present species, is not united with the ovary, and the former is in botanical language inferior; but in the Fuchsia the calyx is so completely united with the ovary that we see no trace of it until we are beyond the berry, and we say then the calyx is superior. It is only a more complete union of calyx with ovary, that makes what might be an Ouograceous plant (Fuchsia) a LytJiraceous one (Cuphea). Again, if we compare it with a mock orange (Philadelphus) or common garden Deutzia (order Saxifragacecz), we shall note that these have several pistils, while in Cuphea there is but one. Normally, however, there are more, and our plant is to be re. garded of so distinct an order simply from the fact that they have been consolidated into one. These little facts help the student much in the knowledge of the relationships of the great families of plants.
Our species has not been found worthy of being admitted to gardens so far, but in a wild state we note a tendency to variation in the size of the petals, and no doubt careful selection might find some forms capable of floral improvement. It is named Cuphea viscosissima - the very clammy Cuphea - from the extreme viscidity of its exudations, greater perhaps than in any other species of the genus. The plant is, indeed, quite as clammy as the Drosera, which is supposed to make use of its glandular hair to catch insects, and in a certain sense to eat them. Our plant is seldom seen without insects adhering to the sticky stems, and it is not at all unlikely that by the aid of the exudation from the glandular hairs the nitrogenous substance of the insect is absorbed and made use of. We have, however, never been able to note the slightest motion in these glandular hairs, as Mr. Darwin observed in the Drosera.
Another singular feature to be noted is that, while in most plants the peduncle or flower-stalk arises from the axil or point just between the stem and the base of the stalk, in this case it comes from between the two opposite petioles. This is a feature common to many other Cupheas. The flower is probably formed from the whole central growth of the axis, and then subsequently pushed out of position by the development and growth of a new central axis or stem. Another very interesting matter is the way in which the seeds are attached on one side only of the placentae, and also the bursting of the capsule, with the thrusting out of the seeds before they are mature. The rupture of the carpel and pushing out of the mass of seeds is done with great rapidity, and is worthy of being closely watched by the observer. The seeds have to ripen after their exposure to the open air, a phenomenon not often met with in the vegetable world. Our artist has shown this feature very well in the plate (Fig. 2).
The geographical relations of this plant are also quite interesting. The home of the genus is in Mexico and Brazil, and there are about a hundred species known, but only two grow within the limits of the United States, and of these, only this one is found to any extent in our country. It may be considered an emigrant from the tropics, and perhaps is still wandering northward. The earlier botanists gave Pennsylvania as its most northern limit, but Dr. Gray, in the later editions of his Manual, locates it as far north as Connecticut. It is mostly confined, however, to the seaboard States, though as we go south it passes the Mississippi and extends down the continent to Brazil.
It has not made its mark in literature in any special capacity.
One single species of the genus has attained some celebrity in Brazil as a febrifuge, but the whole order has little to offer to us so far, but singularity of structure and a petite style of beauty.
Our species is an annual, and is generally found in old fields, or partially shaded waste places.
1. A branch
2. Capsule with immature seeds exposed.
3. Stem, magnified, with captured insect