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Cornus florida. Dogwood.

[image:28286 align=left hspace=1]THE family of Cornels, if surveyed by other eyes than those of botanists, is remarkable for the difference of growth and appearance of its various species. Many of them are shrubs; a few attain to the stature of trees, while some are so humble in their growth as to be deemed hardly more than herbaceous. A part have their flowers surrounded with a fine white involucrum, many times exceeding the whole bunch in magnitude; while others present their naked cymes unadorned by any investment. To the botanical observer they all exhibit a close affinity and resemblance to each other; which is seen in the form and anatomical texture of their leaves, the structure of their flowers and the appearance of their fruit.

The Cornus florida, or flowering Dogwood, is the largest and most splendid of its genus, and is one of the chief ornaments of our forests. A sa tree it is rather below the middle stature, not usually reaching the height of more than twenty or thirty feet. It is however among the most conspicuous objects in the forests, in the months of April, May and June, according to its latitude, being then covered with a profusion of its large and elegant flowers. In Massachusetts, especially about Boston, it is not a common tree, only scattered individuals appearing here and there in the woods. In the Middle States it is extremely common, especially in moist woods. Michaux informs us, that in the Carolinas, Georgia and the Floridas it is found only on the borders of swamps, and never in the pine barrens, where the soil is too dry and sandy to sustain its vegetation. It is also not very common in the most fertile parts of the Western States, being chiefly found where the soil is of secondary quality. [Mr. William Bartram, in his travels in Georgia and Florida,gives the following account of the appearance of this tree near the banks of the Alabama river. "We now entered a very remarkable grove of Dogwood trees, (Cornus florida,) which continued nine or ten miles unalterable, except here and there a towering Magnolia grandiflora. The land on which they stand is an exact level; the surface a shallow, loose, black mould, on a stratum of stiff, yellowish clay. These trees were about twelve feet high, spreading horizontally, their limbs, meeting and interlocking with each other, formed one vast, shady, cool grove, so dense and humid as to exclude the sun-beams, and prevent the intrusion of almost every other vegetable, affording us a most desirable shelter from the fervid sun-beams at noon day. This admirable grove has by way of eminence acquired the name of Dog woods.
During a progress of near seventy miles through this high forest, there constantly presented to view, on one hand or the other, spacious groves of this fine flowering tree, which must in the spring season, when covered with blossoms, present a most pleasing spectacle, when at the same time a variety of other sweet shrubs display their beauty; as the Halesia, Stewartia, Aesculus, Azalea, &c. entangled with garlands of Bignonia, Glycine, Lonicera, &c. &c. at the same time the superb Magnolia grandiflora standing in front of the dark groves, towering far above the common level." Travels, p. 599.]

The genus Cornus is characterized by the following marks. Petals four, superior; involucrum of four leaves, or wanting; drupe with a two-celled nut. The species florida is arboreous, with its flowers in heads surrounded by an involucrum of obovate leaves with recurved points.

Class Tetandria, order Monogynia, natural order Stellatae, Lin. Caprifolia. Juss.

The Cornus florida is of slow growth, and possesses a very compact wood, covered with a rough, broken bark. The branches are smooth, covered with a reddish bark, marked with rings at the place of the former leaves. The leaves, which are small at the flowering time, are opposite, petioled, oval, acute, entire, nearly smooth, paler beneath, and marked, as in others of the genus, with strong parallel veins. The flowers, which are very small, grow in heads or sessile umbels, upon peduncles an inch or more in length. At the base of each bunch is the large spreading involucrum, constituting the chief beauty of the tree when in flower. This involucrum is composed of four white, nerved, obovate leaves, having their point turned abruptly down or up, so as to give them an obcordate appearance. This point has frequently a reddish tinge. Calyx superior, somewhat bellshaped, ending in four obtuse spreading teeth. Petals four, oblong, obtuse, reflexed. Stamens four, erect, the anthers oblong with the filaments inserted in their middle. Style erect, shorter than the stamens, with an obtuse stigma. The fruit is an oval drupe of a glossy scarlet colour, containing a nucleus with two cells and two seeds.

The bark of the Cornus florida is a powerful bitter, possessing also an astringent and somewhat aromatic taste. Both tannin and the gallic acid are abundantly developed in its solutions by their proper tests. In my experiments with the bark of young twigs, but a small quantity of pure resin was made manifest. It would seem that the principal seat of the bitterness is in a variety of extractive matter.

In a valuable inaugural dissertation on the Cornus florida and Cornus sericea by Dr. Walker of Virginia, much attention appears to have been bestowed on the chemical properties of their bark. He found that water distilled from the bark in powder had a transparent, whitish appearance, with a slight aromatic odour, and no perceptible taste. When the heat was increased, the fluid had a lemon colour, with an unpleasant smell and an acerb taste. These effects were probably produced by the volatilization and partial decomposition of portions of the bark in consequence of the heat being continued until the mixture was evaporated nearly to dryness.

With a view to ascertain the effect of different menstrua, Dr. Walker subjected to experiment the residual mass furnished by evaporating a decoction of the root of Cornus florida. Two drachms of this residuum, which had been furnished by seven and an half ounces of the decoction, were macerated in successive quantities of the best alcohol, until the last portion ceased to be changed in colour and taste. The part, which remained undissolved, weighed only half a drachm. When redissolved it was destitute of taste, and underwent no change of colour on adding the test of iron. The alcohol, which had been employed in the experiment, was found to possess an intensely bitter taste with astringency, of a clear red colour, and turning to a deep black on the addition of iron. On evaporation, it yielded a drachm und an half of residuum.—Dr. Walker attempted to ascertain the quantity of resin by macerating the alcoholic extract in repeated portions of sulphuric ether. The ether acquired a dark colour and a bitter taste, and was found to have dissolved three quarters of the extract. When tested with iron, it was found that the remaining quarter only was changed to a black colour.

The Cornus florida is one of the many vegetables which, by the union of their gallic acid with the salts of iron, form a black compound, applicable to the purposes of ink. The constancy of the black colour thus produced varies greatly, according to the substance from which the gallic acid is derived. It is often extremely fugacious, sometimes fading in a few days, and at others becoming indistinct after some weeks or months. Considering the very great importance of the purposes for which ink is employed, and the immense evils which may result from its obliteration in writings intended for permanency; it is with extreme caution that we should recommend the introduction of any change in the mode of its formation. The oak gall has had the experience of ages in favour of its permanence and immutability. It is not until some indigenous article, producing an equal intensity of colour, has undergone a series of trials from time and exposure, sufficient to establish beyond a doubt its durability, that its substitution in the manufacture of ink should be considered expedient or even justifiable.

Upon the human body the bark of the Cornus florida acts as a tonic, an astringent and an antiseptic, approaching in its general effects to the character of the Peruvian bark. From a variety of experiments made by Dr. Walker upon the healthy system, it was found that this medicine uniformly increased the force and frequency of the pulse, and augmented the heat of the body. Collateral experiments were made at the same time with the Peruvian bark, with which the Cornus appeared to agree both in its internal and external effects.

In disease it has been principally employed in the same cases for which the cinchona is resorted to, particularly intermittent and remittent fever. Dr. Gregg of Pennsylvania, cited by Dr. Walker, states, that after employing the Cornus florida habitually for twenty three years in the treatment of intermittents, he was satisfied that it was not inferior to the Peruvian bark as a means of cure in such cases. Among the number of cures by this medicine, was that of his own case. He observed that in its recent state it sometimes disagreed with the stomach and bowels, but that this tendency in the article was corrected by age. He recommends the bark as being in the best state after it has been dried a year.

Other medical men have employed the bark of this tree with advantage in intermittents, and also in continued fevers of the typhoid type. Its tonic operation in these cases appears very analogous to that of the Peruvian bark.

I have employed the tincture of Cornus florida as a stomachic in various instances of loss of appetite and indigestion. The report of those who have taken it has perhaps been as frequently in favour of its effects, as of gentian, columbo, and the other imported tonics of the shops, though perhaps it is somewhat more liable to offend the stomach in large doses. In the Southern States a decoction of the buds and twigs has been thought to agree better with weak stomachs, than the other preparations.

Some other species of this family resemble the present tree in the bitterness and tonic power of their bark, particularly the Cornus circinata and C. sericea.

The wood of the Cornus florida is hard, heavy and fine grained, and susceptible of a good polish. It is employed, for various purposes where strength and solidity are required, although its small size does not permit it to be used for objects of much magnitude. From its hardness it is found peculiarly useful for handles of instruments, the teeth of wheels, and the smaller parts of wooden machinery.

Botanical References.

Cornus florida, Lin. Sp. pl.
Gronovius, Virg.17.
Kalm, travels, ii 321.
Wangenheim, Amer. p. 51, t. 17.
L'Heritier, Corn. ii. 3.
Schmidt, Arb. t. 62
Botanical Mag. t. 526.
Pursh, i. 108.
Michaux, Fil. Arbres forestiers, iii. 138, translated, i. 255.
Elliott, Car. i. 207.
Cornus mas Virginiana, &c.
Plukenet, Alm. 120, t. 2, f. 3.
Catesby, Car. t. 27.

Medical References.

Walker, Inaugural Dissertation, Philad. 1803.
Bart. Coll. 12.
Thacher, Disp. 203.
Elliott, ut supra.


American Medical Botany, 1817-1821, was written by Jacob Bigelow, M. D.



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