Cassia tetraphylla

  • Title

    Cassia tetraphylla

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Cassia tetraphylla Martyn

  • Description

    158.  Cassia tetraphylla Martyn in Miller, Gard. Diet. ed. 9, 1: Cassia no. 44. 1797, based on C. procumbens Miller, Gard. Diet. ed. 8, Cassia no. 20. 1768 (non C. procumbens L., 1753).—" .sent me from La Vera Cruz [Mexico] by the late Dr. Houston."—Holotypus, BM! = Bailey Hort. Neg. 5171; presumed isotypus (fragm), LE! — C. tetraphylla sensu Colladon, Hist. Casses 130. 1816; Irwin & Barneby, Brittonia 28 (4); 441. 1977.

    Cassia hispidula Vahl, Ecl. Amer. 3: 10. 1807. — "Habitat in America meridionali. von Rohr." — Holotypus, C (hb. Vahl.)! = NY Neg. 6756. — Grimaldia hispidula (Vahl) Britton & Rose, N. Amer. Fl. 23: 299. 1930. — C. hispidula sensu Bentham, 1870, p. 131, t. 35, fig. 2; 1871, p. 559 (exclus. syn. C. fagonioide).

    Cassia hispida Colladon, Hist. Casses 118. 1816. — "Hab. Cayennae. (Patris v.s. sp. h. DC.)'' — Holotypus, G-DC! = F Neg. 7006.

    Cassia pauciflora Humboldt, Bonpland & Kunth, Nov. Gen. & Sp. 6 (fol): 360. 1823. — "Crescit in Regno Mexicano, prope La Venta del Peregrino [between Acapulco and Chilpan- cingo, Guerrero, on the seaward slope] , alt. 180 hex." — Holotypus, P-HBK (no. 3907)!

    Cassia lotoides Humboldt, Bonpland & Kunth, Nov. Gen. & Sp. 6 (fol): 361. 1823. - "Crescit prope Caripe Cumanensium [Estado Sucre, Venezuela], alt. 412 hex; item locis arenosis prope El Capuchino, ad ripam Orinoci." — Holotypus, P-HBK! isotypus, Bonpland 261 from Caripe, P! = NY Neg. 6915.

    Cassia leiantha Bentham, J. Bot. (Hooker) 2: 78. 1840. — " . .sent by Schomburgk in some collections [from British Guiana] under n. 64." — Holotypus, K (hb. Benth.)! = NY Neg. 1476; isotypi, G, LE, P!

    Grimaldia confusa Britton & Rose, N. Amer. Fl. 23: 300. 1930. — ''Type from near the city of Oaxaca [Mexico], June [16—21], 1899, Rose & Hough 4654.'' — Holotypus, US! clastotypus, NY! — Cassia rosei Standley, Field Mus., Bot. 18: 518. 1936 (non C. confusa Phil., 1894).

    Low, usually slender, diffusely procumbent or weakly assurgent subshrubs with few to several, when short simple, commonly from below middle widely branching stems (1-) 1.5-7 dm arising annually from a blackish knotty rootstock or xylopodium, highly variable in pubescence, the stems and lf-stalks to various degrees villosulous and setulose or setose, either villi or setae predominating or the villi O, exceptionally glabrate almost throughout, the lfts when fresh often zonate, the inflorescence nearly always densely viscid-setose or setulose (setae up to 0.32.5 mm), the racemes terminal to short simple stems but the longer stems becoming sympodial, the lower racemes then becoming lf-opposed and often far overtopped by the associated axillary branchlet.

    Stipules erect or narrowly ascending, slenderly subulate to triangular-subulate, (0.5-)0.8-2 (-2.5) mm, persistent.

    Lvs ascending and widely spreading 2-6(-7) cm, those low on the stem spirally, those of upper stems often subdistichously arranged, all slender-petioled; pulvinus moderately or scarcely dilated but very often discolored, 0.8-1.6 mm; petiole (1-) 1.3-3.5(-4) cm, at middle 0.3-0.55(-0.7) mm diam, tapering distally, very narrowly obtusely winged ventrally, the sulcus shallow; rachis (1.5-)2.5-6(-10) mm; lfts 2 pairs, the distal often a trifle larger, both tilted forward from rachis, turned half face to face on linear-oblong, ventrally depressed, discolored but scarcely dilated, when dry cross-wrinkled pulvinule (0.6-)0.8-1.4(-1.8) mm, in outline either broadly obovate and obtuse to emarginate, or ovate-elliptic obtuse, or rhombic-elliptic and subacute, minutely mucronulate, (4.5-)6-26(-32) x 3.5-18(-23), at asymmetric base on both sides broadly cuneate or on distal side shallowly cordate, the plane margin entire, smooth or less often setose, the blades chartaceous or subcoriaceous, on both sides dull olivaceous, dull dark green, or subglaucescent, when fresh often red-margiried and either pallid- or red-maculate along midrib and secondary veins, the faces commonly glabrous, subglutinous, less often setose dorsally or on both sides viscid-villosulous.

    Racemes either single and terminal or on sympodial stems lateral and lf-opposed, rarely by suppression of some upper leaves incipiently paniculate, loosely or remotely (1-)3-20(-30)-fld, the axis either straight or abruptly flexuous, (2-)4-15(-20) cm, the one expanded flower standing ± at level of succeeding buds; bracts ovate-triangular or subulate, 0.7-1.6 mm, persistent; pedicels 1-2.6(-3.3) cm, in fruit either divaricate and strongly incurved or deflexed and geniculate under the fruit, bracteolate 2-9(-13) mm below calyx; bracteoles resembling bracts but 0.4-1.6 mm, tardily deciduous; buds ovoid, sharply apiculate, densely to thinly setose, setulose, or rarely glabrous; sepals submembranous, brownish-yellow, reddish, or bright red, (7.5-)8-13 x 2-4.6 mm, the outer ones lance-elliptic, always acute or subacuminate, the broad inner ones abruptly apiculate; petals at anthesis widely ascending, yellow, sometimes basally reddish, commonly fading bright orange the second day, the 4 plane ones broadly oblanceolate to spatulate, slender-clawed, 12-18 x 5.5-8.5 mm, all alike or 1-2 shorter, the fifth slightly longer, falcately half-ovate, 14-19.5(-20) x 8-13.5 mm, the convex crenulate margin folded back over the androecium; ovary densely hispid; ovules (5-)6-9 (-11).

    Pod linear-oblong, (2.6-)3-5 x 0.55-0.85 cm, the castaneous, glutinously lustrous valves almost always hispid with spreading setae up to (1.2-) 1.5-4(-5) mm and often also minutely viscid-

    villosulous, the villi often wanting and the setae sometimes few, exceptionally absent, seeds 3.1-5.1 x 2.5-3.1 mm, the dark brown or almost black testa not highly lustrous, strongly lineolate. - Collections: 258.

    Savannas and grassy openings, especially in sandy soils, in coastal or lowland scrub thickets, pine-barrens, palm-barrens, in n.-e. Brazil locally common on coastal dunes and entering caatinga, in Central America ascending in the pine-oak belt up to 1200, exceptionally 1600 m, adapted to climates with a pronounced dry season, resistent to burning but palatable to stock and vulnerable to grazing, widely dispersed along and near the Atlantic coast of South America from Bahia, Brazil, to Trinidad, in Brazil extending w. interruptedly to isolated savannas in the lower Amazon valley in Para and on upper Rio Branco in Territorio Roraima near the Guyana border, apparently greatly isolated (? introduced) in centr. Mato Grosso (Cuiaba), in Venezuela w. through the Orinoco lowlands to Apure but on the Caribbean slope only in Sucre (including Is. Coche and Margarita) and Anzoategui; n.-e. Colombia (Norte de Santander); not recorded from Panama; w. Cuba (Las Villas, Matanzas, and Pinar del Rio with I. de Pinos); and again widespread in Central America from Costa Rica to British Honduras and s. Mexico (Chiapas, Oaxaca, Tabasco, centr. Veracruz but not recorded from Yucatan Peninsula), and interruptedly w. along the Pacific seaboard to 104° 40 W in s. Jalisco. — Fl. especially in wet season after rains, and well into the dry season.

    Cassia tetraphylla makes a convenient standard of comparison for a group of weedy, diffuse, weakly suffrutescent or essentially herbaceous but stoutly perennial Absus cassias that resemble the annual C. (Grimaldia) absus in habit of growth, in the long-petioled quadrifoil leaves and sympodial stems, but differ collectively in a woody perennial root combined with widely expanding, brightly colored perianths and decamerous androecia. The members of the group most closely related to C. tetraphylla are C. fagonioides and C. pauciflora, both of which differ in their obtuse sepals and consequently bluntly rounded flower-buds.

    As might be expected from its great distributional range, C. tetraphylla is a polymorphic species, the plants varying in vigor, in shape, size and mottling of the leaflets, in color of the flower, and most notably in the density, length, and composition of the pubescence and its dispersal through the foliage and inflorescence. Young plants or old ones regenerating after fire may consist of one or few simple stems only 1-2 dm long ending abruptly in a solitary raceme, but stems of adult, normally well-developed plants early become diffusely branched, and may continue through an extended season of active growth to develop a series of sympodial axes rising beyond the morphologically terminal but in effect lateral and leaf-opposed inflorescences. Collectors of C. tetraphylla have repeatedly noted decoratively mottled or variegated foliage, but the patterns and colors seem to be quite variable. Some leaflets are red-margined and pallid along the midrib and secondary veins; some are coarsely green-veined against a brownish field; yet others are described as marbled, sometimes on a glaucescent ground or blotched with red at base or middle. These patterns fade rapidly in drying and few specimens show more than a trace of the original discoloration, which is in any case not universally characteristic of the species. Bright pigmentation is perhaps accentuated in poor sandy soils, where the leaflets tend to be small and thick in texture, but we have no organized information on this point. Similarly the petals are described as either yellow, or yellow reddish-tinged at base, or orange, this applying at least sometimes to the newly opened flower, not to the always discolored fading corolla. But as yet no correlation between color and other variable features can be made out.

    Leaflets of C. tetraphylla are most commonly broadly obovate and obtuse to shallowly emarginate, and this type is found throughout the full range. In Central America commonly, elsewhere sporadically, the leaflet outline varies by imperceptibly small gradations into elliptic, oblong-elliptic, or rhombic, the tips finally becoming acute or almost so. The extreme forms are visually arresting, but the intermediate ones are far too numerous to permit taxonomic division of the species on these lines.

    The pubescence of C. tetraphylla, like that of most kindred species, consists of villi and basally enlarged setae, but the proportions of the two sorts and the length and position of the setae are subject to much random variation, sometimes sufficiently pronounced to determine the aspect of the plant. Using pubescence as point of departure, our material of C. tetraphylla can be divided arbitrarily into two groups of about equal size: in one of them, long seate (over 1 mm) predominate along the upper stems and associated leafstalks, often extending upward through the inflorescence but almost as often diminishing or disappearing distally, especially along the pedicels and calyx; in the other mixed villi and setules (less than 1 mm) clothe stems, leafstalks and inflorescence alike, mixed perhaps with a very few longer setae scattered over some medial or distal petioles. Sorted thus, the first type emerges as the commoner one southeastward from the mouth of the Orinoco River, but occurs northward sporadically into Mexico (Veracruz); whereas the second type, which prevails in Central America, becomes progressively rarer southward and eastward from the Orinoco valley, nevertheless attaining outposts as far east at Paraiba in Brazil. In the lower Orinoco valley, in Trinidad, and in western Cuba, forms intermediate between the idealized types are so numerous that no practical division on the basis of pubescence can be attempted. It seems likely, nonetheless, that there is some real correlation between a more coarsely and amply leafy growth-habit and pronounced setose vesture, just as a neatly thrifty, smallleaved habit goes hand-in-hand with shorter vesture. Possibly these linked characters are both ecologically selected.

    So far we have considered only those forms of C. tetraphylla with glabrous leaflets. Sporadically almost throughout the full species range the setae or setules of the leafstalk extend out along the midrib of the leaflets and some secondary veins, less often to the leaflet margins which in becoming ciliate become also obscurely crenulate. Setose-ciliolate leaflets usually of obovate but sometimes of elliptic outline, have been encountered in northeast Brazil (Paralba, Rio Grande do Norte, Ceara, Para), Trinidad, and Central America (Honduras, El Salvador, Chiapas). A more emphatically marked variant in which a fine villosulous vesture mixed with setules extends to the faces of the leaflets, which again may be either obovate or elliptic in outline, is prevalent between 800 and 1200 m in the pine-oak belt of the Central American highlands between Oaxaca and Costa Rica. It has been found, however, as low as 300 m in Guatemala and does not fully replace the glabrate form in the upland habitats, the latter having been recorded at 8-900 m in Mexico (Chiapas) and at 1050-1350 m in Guatemala (Huehuetanango, Quiche) and Honduras (El Paraiso). The leaflets of this pubescent form tend to be relatively thick-textured, therefore often coarsely rugulose when dry. This is especially true of populations from the valley of central Oaxaca, one of which furnished the type of Grimaldia confusa. But in the very same region there occurs a habitally identical form, with equally thick but glabrous leaflets (Liebmann 5005) and an almost identical phenotype has arisen, presumably independently, in the caatinga of Ceara (Lofgren 722). For these reasons we treat C. confusa (Cassia rosei) as a synonym. Interestingly enough the same vernacular name, naguache, has been found in use for all of the extreme variants of C. tetraphylla known to occur in Central America.

    It remains only to mention the opposite extreme variant in pubescence described by Bentham as C. leiantha. Here the vesture of the whole plant is suppressed or reduced to a remnant of minute setules, the sepals and sometimes the pod also becoming smooth and glabrous. The type of C. leiantha was part of a mixed collection from Guyana, very nearly duplicated by one from the Orinoco valley in Bolivar, Venezuela (Ll. Williams 11954), in which some individual plants have glabrous pod combined with hispidulous raceme-axis, whereas others are fully hairless. Very similar phenotypes have been met with in Costa Rica (Orsted 4974), Honduras (Standley & Lindelie 7352) and Oaxaca (E.W. Nelson 2732). Bentham's evaluation (1871, I.c.) of C. leiantha as an individual variant of C. tetraphylla is certainly correct.

    With due allowance made for the variation described, our comprehensive concept of C. tetraphylla very nearly coincides with that of Bentham's summary revision (1871) differing only in so far as we maintain the closely related and partly sympatric C. fagonioides as a distinct species.