On the Presence of Pipitzahoic Acid in the Perezias Found in the Territory of the United States,
and on the Geographical Distribution of the North American Species of that Genus.
By CHARLES MOHR, Mobile, Ala.
Translated by the Author from Pharmaceutische Rundshau.
The remarks on pipitzahoic acid which appeared in the "Rundschau" of November has directed the attention of the writer anew to a subject in which he felt himself greatly interested during his stay in Mexico in 1857, where he got acquainted with the publication of the researches of Rio de la Lozas, announcing his discovery of this peculiar organic acid, made a short time before. The inquiries after its source, the "Raiz del Pipitzahuac," made in consequence at the time in the leading drug houses of the city of Vera Cruz and at Orizava were leading to no results. Amongst the varied stock of the numerous drugs derived from Mexican plants no root was found of that name, and only a single species of Perezia was encountered during the frequent botanical excursions made in these parts of the Mexican republic, also the only one found amongst the large collection made by the botanist Bolteri, of Orizava. After a lapse of many years the determination of this plant was only made possible a few weeks ago, since the review of the North American Perezias by Prof. Gray has come to hand, where it is described under the name of Perezia Dugesii. (Gray, "Proceed. Am. Acad. Arts and Sciences," vol. xix, Oct., 1883.)
These plants seem to shun the damp clime of the eastern declivity of the Mexican Andes; they are rather plants of the desert regions, finding their proper home, with the widest distribution, in the rainless, arid plains (mesas), and on the rocky hills of the highlands of northern Mexico and the adjoining parts of the United States.
The genus Perezia, Lag., as defined by Gray, (Gray, loc. cit., and Botany of California, vol. 1.) embraces bilabiate compositae of the sub-order Labiatiflorae and the tribe Mutisiaceae, with perfect and throughout homogeneous flowers, united to a greater or lesser number in heads with a naked receptacle, surrounded by a campanulate or top-shaped involucrum of stiff elongated more or less lanceolate scales, imbricated in two or more rows. Corolla with a slender tube, distinctly two-lipped, with the three-toothed exterior lip longer than the interior, with two teeth; the anthers are long caudate, with a more or less prominent lanceolate tip or crest-like appendage. The akenes are elongated cylindrical or slightly angled, often somewhat spindle-shaped, with a discoid, apex, bearing a pappus of copious capillary, somewhat scabrous bristles. All the species are perennials with more or less rigid leaves, with the simple stem bearing the white or purplish flowers in solitary heads or in corymbs. They are exclusively confined to the warmer parts of the American continent, and the 40 or 50 species known are equally divided between its southern and northern divisions. Those occurring in the latter are found in the highlands of Mexico and the adjacent parts of Central America, extending beyond the Mexican border into the territory of the United States as far north as the 34° of north latitude.
The North American species belong all to a group distinguished by the similarity of all the florets within one head, the three-toothed exterior lip of the corolla being even in the marginal flowers, scarcely if at all longer than the interior, forming the well-marked natural section Acourtia, established first as a proper genus by De Candolle. In the group embracing the South American species, the Perezias proper, found mostly south of the Equator, the interior lip of the corolla is considerably shorter than the ligulate exterior. For the establishment of the characters of the species belonging to the first of these groups, and for the determination of the limits of their distribution, we are indebted to Prof. Gray, who has particularly given many years of his arduous labors to the elucidation of the most prominent feature of the North American flora, the difficult order of Compositae, with such eminent and distinguished success. The characters of these plants were before but vaguely defined, and variously understood; hence we find them referred to various genera; some were described under the genus Dumerilia, Less., others as species of Trixis and Proustia, section Thelecarpus and Acourtia, D. C. Of the 24 North American species recognized by Gray seven are found within the southwestern territory of the United States; they were mostly brought to light during later years by the explorations of the arid regions between southwestern Texas and the Pacific Ocean. The first five of the species enumerated below, the flora of the United States has in common with northern Mexico, and the two following seem to be confined to its limits.
Species found in the United States.
1. Perezia nana, Gr., Pl. Trendler 110, and Plant. Wright., i, 125, seems to be the most frequent, being found in all the collections made in Southwestern Texas, Southern New Mexico, all parts of Arizona and the adjacent parts of Mexico.
2. Perezia runcinata, Lag., from Chihuahua and Sonora to Arizona, and New Mexico as far east as the Colorado river in Texas, where it is not rare on the rocky hills near Austin.
3. Perezia Thurberi, Gr., Pl. Thurb., Sonora, Southern Arizona.
4. Perezia Wrightii, Gr., Plantae Wrightianae,—P. arizonica, Gr., Flor. Cal, not rare from Southwestern Texas and Southern Utah through Arizona to San Louis Potosi (Schaffner).
5. Perezia Parryii, Gr., Proc. Am. Acad. Sci. and Art, vol. xv. Southern Arizona.
6. Perezia Wislizeni, Gr., Plant. Fendl. Southern New Mexico.
7. Perezia microcephala, Gr., Acourtia microcephala, D. C. Coast of Southern California (Santa Barbara, Monterey).
Species of Northern Mexico.
8. Perezia formosa, Gr., P. turbinata, Gr. , Pl. Wright., non Llav. et Lex. Acourtia formosa, Don. A. macrocephala and Trixis turbinata, Schultz Bip. Leg. Seemann.
9. Perezia thyrsoidea, Gr. Bot. Mexic. Bound. Surv., leg. Borland.
10. Perezia Seemannii, Gr. Pl. Wright., leg. Seem. Northwestern.
11. Perezia Coulteri, Gray. Proc. Am. Acad. xv. Leg. Coult.
12. Perezia patens, Gr. Acourtia formosa and Trixis patens, Schultz Bip.
13. Perezia platyphylla, Gr. Fendler, leg. Coulter, Zimapam.
14. Perezia rigida, Pl. Gr. Pl. Wright. l. c. Acourtia rigida, D. C. A. formosa, Hook. et Arn.
Species of Central Mexico.
15. Perezia adnata, Gray. This is the mother plant of the Raiz del Pipitzahuac of the natives, brought, first to the notice of European botanists by Schaffner, who collected the plant near Tolucca. Trixis Pipitzahuac, Schaffner et Schultz Brp., Dumerilia Alami, D. C. Perezia Alami, Hemsia Biol. of Central Americ., Bot. ii. Morelia legit Giesbrecht.
16. Perezia hebeclada, Pl. Wright. Acourtia hebeclada, D. C.
17. Perezia turbinata, Llav. et Lex. Valley of Mexico, legit Schaffner.
Species of Eastern and Southern Mexico.
18. Perezia oxylepis, Gr. Proceed. Am. Acad., xv. Puebla? Liebman.
19. Perezia carpholepis, Gr. Acourtia carpholepis, Schultz Bip. Liebman.
20. Perezia Dugesii, Gray. Proc. Am. Acad., xix., Guauaxuato Duges leg. Acourtia spec. Plant. Botteriana. 1172. Orizava. Botteri, Mohr legit 1857.
21. Perezia moschata, Llav. et Lex. Chiapas, Giesbrecht.
22. Perezia reticulata, Gr. Proustia reticulata, Lag. Dumerilia reticulata, Don. From the Valley of Mexico to Oaxaca, Galeotti.
23. Perezia fruticosa Llav. et Lex. A dubious species.
24. Perezia nudicaulis, Gray. Plant. Wright. Republic Guatemala, Skinner.
Of the species occurring in the United States, the writer has obtained specimens of two species, Perezia nana and Perezia Wrightii, for which he is indebted to the kindness of Messrs. Lemmon and Pringle, zealous botanists who have spent the past season in the botanical exploration of Arizona and Southern California. The roots attached to several specimens furnished sufficient material to establish the presence of pipitzahoic acid, and the specimens of great perfection served as originals for the accompanying illustrations of these most interesting plants.
Perezia nana Gr., of slender growth from 4 to 8 inches high, with a slender, creeping or ascending root-stock, articulated mostly, and the joints and head of which are covered with tufts of fine woolly hairs. The slender wiry stem is simple or sparsely branched from the base, slightly flexuous, angled and a little rough. The rigid, coriaceous leaves are shining, glandular, scabrous, strongly reticulate veined, roundish ovate, 1 ½ to 2 inches wide and but little longer, spinose toothed, sessile by a cordate base or amplexicaul. The large capitula are terminal, subsessile, 20-30 flowered with a campanulate involucre of mucronate cuspidate, ciliated scales, arranged in three rows, of which the exterior ones are ovate and the interior lanceolate, all purplish towards the apex. The akenes are whitish, glandular, puberulent, cylindrical, and have a pappus of copious hairs.
The root of a slightly bitter and astringent taste, imparts to strong alcohol a dingy yellow tint, which by the addition of a weak solution of a caustic alkali deepens to a clear deep yellow color. If a very dilute solution of sodic or potassic hydrate is carefully added, a faint and evanescent tint of impure purple color is perceptible, indicating the presence of small quantities of pipitzahoic acid combined with another substance. As would be expected by the deepening of the color, in consequence of the addition of an alkali to the tincture, this substance proved to be a tannic acid, ferric chloride producing an abundant precipitate of dark green color, which disappeared by the addition of oxalic acid. To obtain the pipitzahoic acid pure, the alcoholic tincture of the root was treated with boiling water, and the very minute quantity of a golden yellow crystalline precipitate washed by decantation. Examined under the microscope it was seen to form stellate groups of acicular or dagger-shaped golden yellow crystals characteristic to this compound, which by the addition of a drop of diluted solution of sodic hydrate are dissolved with the production of a beautiful deep violet color. Incomplete as the chemical investigation of the few decigrams of the root of this plant at command must appear, its results show that as a source of pipitzahoic acid, it is of but little value, which in reference to the therapeutical virtues claimed for tills substance as a mild purgative, is further impaired by the largely predominating quantities of tannic acid with which it is associated. Of greater interest, in that respect, containing considerable quantities of pipitzahoic acid in an almost pure state, was found the following species:
Perezia Wrightii, Gr. This is a robust plant from 1 to 2 feet in height, with a woody tap root on all sides covered by a dense cushion of long silky dark brown hairs; freed from these, it is found more or less contorted, over an inch long and 1 of an inch in thickness. The transverse section shows, when examined under the microscope, numerous fibro-vascular bundles, separated by the intervening cortical substance. Stem erect, simple below, corymbosely branched above, smoothish, the lower part covered by the leaves which are membranaceous, 3 to 4 inches long, 2 to 3 inches broad, glabrous, strongly ribbed, unequally serrated and spinulose denticulate, closely sessile, with an auriculate or cordate base. Flowering heads numerous, small, with short, glandular hairy, subulately bracted pedicels, terminating in dense clusters the branches of the open, nearly naked corymb, containing 8 to 10 flowers. Involucre small, scarcely exceeding, in length, the fruit; the scales to the number of 12 to 15, are rather membranaceous, greenish, viscid puberulent, the innermost oblong linear, the exterior shorter, oblong-ovate. Akenes 5 ribbed, somewhat fusiform, bearing a pappus of copious, soft, white, capillary bristles.
The root is of a bitterish, not disagreeable taste. The alcoholic extract is of a pure deep yellow color; treated with an excess of boiling water it yields an abundant crystalline, golden yellow precipitate of pipitzahoic acid, which, by the addition of a dilute solution of caustic alkali shows the characteristic splendid reaction already described. From these observations it is evident that the roots of Perezia Wrightii will serve as a fit material for the preparation of this acid in larger quantities.
According to Prof. Gray, (Rep. Mexic. Bound. Sur. Botany.) Perezia runcinata possesses thick, tuberous roots similar to those of the dahlia. Unfortunately I could not procure specimens of this plant, found nearest to the limits of our eastern North American flora. I am, however, in hope to obtain them before the close of another season, as well as a sufficient supply of the roots of Perezia Wrightii for the preparation of larger quantities of this highly interesting and peculiar organic constituent of the North American Perezias, so as to be able to study closer its properties, and obtain some light in regard to the uses to which it might possibly be applied to in the laboratory and in the arts, as well as to permit of a closer investigation of its value as a remedial agent.
Mobile, December, 1883.