Monographs Details: Cassia chartacea H.S.Irwin var. chartacea
Authors:Howard S. Irwin
Authority: Irwin, Howard S. 1964. Monographic Studies in Cassia (Leguminosae-Caesalpinioideae). I. Section Xerocalyx. Mem. New York Bot. Gard. 12 (1): 1-114.
Family:Caesalpiniaceae
Synonyms:Cassia uniflora var. latifolia Benth.
Description:Latin Diagnosis - Planta fruticosa aut suffruticosa erecta, plerumque ramosissima, ad 1.5 m alt. Caules puberulentes aut iuvenes pubescentes. Stipulae adpressae persistentes, caulem superiorem partim celantes, lanceolato-cordatae aut anguste ovato-cordatae, longo-acutae aut-acuminatae, 6.1-9.0 mm long., 2.0-3.1 mm lat., glabrae, saepe quasi glaucae, ciliolatae integrae. Petiolus tenuis, 4.2-6.0 mm long., canaliculo adaxiali puberulente, superficie abaxiali pubescente aut pilosa pilis distaliter directis; rachis 0.3-0.5 brevior quam petiolus, saepe sursum arcuata, terminaliter aristata. Glans 1, plerumque scutellata, 0.2-0.4 mm lat., sessilis, saepe depressa atque non perspicua. Foliola bijugata, raro trijugata, paribus subaequis aut pari superiore paululum longiore, per pulvinulum parvum arcuatum atrum aut brunneum aut subflavum 0.2-0.5 mm long sessilia, oblanceolata,, paululum obiqua, recta aut laminae superiores interdum divergentes, glabrae saepe glaucae, membranaceae papyriferaeve, 1.2-2.5 cm long., 0.3-0.5 cm lat., cinereo-virides; margines integri ad apicem rotundatum obtusumve saepe ciliolati. Flores axillares, plerumque singulares; pedicellirecti, unilateraliter aut omnino puberulentes, 1.6-2.1 cm long., c. 0.3 mm crass. dum florentes, usque ad 2.8 cm long., 0.5 mm crass. dum frugiferentes; bracteae 2, lanceolatae ad ovatae, 2.0-3.1 mm long., 0.7-1.4 mm lat.; bracteolae suboppositae, lanceolatae, 3.9-5.1 mm long., 1.2-1.4 mm lat., sepala aut anguste ovata, glabara, 1.9-1.4 cm long., 2.7-3.4 mm lat.; petala dilute flava, vexillo maculam subroseam interdum praebente (e.g. Irwin 2420), 1.2-1.6 cm long., 0.9-1.4 cm lat.; stamina flava aut straminea; ovarium flavumaut cinereo-pilosum. Siliqua anguste oblonga, 2.7-3.4 cm lang., 4.5-5.7 mm lat., plana aut quasi plana, parce adpresso-pilosa. Semina 10-15 levia dura brunnea atrave, paululum compressa, 3.0-4.2 mmlong., 0.7-1.2 mm lat.

Species Description - Erect shrub or subshrub, usually much-branched, to 1.5 m. Stems puberulent or pubescent when young. Stipules partly obscuring upper stem. lanceolate-cordate or narrowly ovate-cordate, long-acute or -acuminate, 6.1-9.0 mm long, 2.0-3.1 mm broad, glabrous, often somewhat glacous, ciliolate. Petiole slender, 4.2-6.0 mm long, the adaxial groove puberulent, the abaxial surface subescent or pilose with distally-directed hairs; rachis 0.3-0.4 mm broad, sessile, often arched upward. Gland 1, usually scutellate, 0.2-0.4 mm broad, sessile, often depressed and obsucure. Leaflets bijugate, rarely trijugate, the pairs subequal or the superior pair slightly longer, joined to rachis by a small arcuate black, brown or yellowish pulvinule 0.2-0.5 mm divergent, glabrous, often glaucous, membranaceous or papyriferous, 1.2-2.5 cm long, 0.3-0.5 cm board, gray-green; margins frequently ciliolate at the rounded or obtuse apex . Flowers usually solitary; pedicels straight, somewhat flattened, unilaterally or wholly puberulent, 1.6-2.1 cm long and ca. 0.3 mm thick in flower, up to 2.8 cum long and 0.5 mm thick in fruit; bracts 2, lanceolate to ovate, 2.0-3.1 mm long, 0.7-1.4 mm board; bracteoles subopposite, lanceolate, 3.9-5.1 mm long, 1.2-1.4 mm broad; sepals lanceolate or narrowly ovate, glabrous, 1.0-1.4 cm long, 2.7-3.4 mm broad; petals 1.2-1.6 cm long, 0.9-1.4 cm broad, the banner occationally with a pink blotch (e.g. Irwin 2420); ovary yellow- or gray-pilose. Pod narrowly oblong, 2.7-3.4 cm long, 4.5-5.7 mm broad, flat or nearly so, sparcely appressed-pilose. Seeds 10-15, slightly compressed, 4.0-4.2 mm long, 0.7-1.2 mm broad. Chromosome number: not determined.

Distribution and Ecology - Distribution: Brazil, central and western Minas Gerais and southern Goiás south to central and western São Paulo. Possibly also in western Pernambuco and in central Paraná. Occuring in rocky and sandy hills and savanas, from 750 to 3000 feet elevations. Brazil. Goiás: 20 km N of São João de Allianca, 13 Apr. 1956, E. Y. Dawson 14160 (NY); Vargem Grande in Chapadão dos Veadeiras, w/o date, Glaziou 20990 (MG, P, S in part, UC in part, US in part): Minas Gerais: Caxoeiras do Campos, 1839, Claussen (& Delessert?) s.n. (K); w/o locality, 1840, Claussen s.n. (BM); w/o locality, Claussen 1 (F, GH, MICH); w/o locality, w/o date, Claussen 80 (F); Serra da Caracól, 10 Feb. 1874, Gillosin 1247 (S); Environs de Rio Janeiro et d'Ouroo Preto, 1883-1884, A. Glaziou 14531 (K); w/o locality, w/o date, A. Glaziou 19088 (NY); Pocos de Caldas, 27 Jan. 1919, F.C. Moehne 2922 (BM); Logôa Seca, Serra do Curral, Município de Belo Horizonte, 2 Jan. 1959, H.S. Irwin 2364a (TEX); Lagôa Seca, Serra do Curral, Municípo de Belo Horizonte, 2 Jan. 1959, H.S. Irwin 2365 (MICH, NY, R, TEX, UC, US, VIC); Serra Rola Moça, ca. 10 km E of Barreiro, Municipo de Contagém, 7 Jan. 1959, H.S. Irwin 2390 (MICH, NY, R, TEX, UC, US, VIC); Serra do Itabirito, 5 km W of Cachoeira do Campo, 11 Jan. 1959, H.S. Irwin 2420 (MICH, NY, R, TEX, UC, US, VIC); 41 km S of Carmo de Paranaiba, on rd. to Rio Paranaiba, 10 Feb. 1959, H.S. Irwin 2617 (MICH, NY, R, TEX, UC, US, VIC); Ponte Queimada-Extraccão, Diamantina, 19 Nov. 1937, Mello Barretto 9847 (F, US); Caldas, Pedra Blanca, 9 May 1892, Regnell II 74 (S); Caldas 19 Jan. 1965, Regnell II 74 (K, NY, S, US); Serra de Caldas, 1875, Regnell II 74 (S); w/o locality, w/o date, Regnell II 74c (S); w/o locality, 1845, Widgren s.n. (S, U); Serra da Mutuca, hills near Lagôa Seca, near Belo Horizonte, 22 Feb. 1945, L.O. Williams & Assis 5589 (GH); Serra da Mutuca, Municípo of Nova Lima, Feb. 1945, L.O. Williams 5693 (GH); Inn campo, Bento Pires, Belo Horizonte, 13 Mar. 1945, L.O. Williams & V. Assis 5940 (US); Morro das Pedras near Belo Horizonte, 4 Mar. 1945, L.O. Williams & Assis 5981 (F, GH); Near Lagôa Pampulha, Municipio of Belo Horizonte, 8 Mar. 1945, L.O. Williams & F. Assis 6079 (GH, MO, SI, UC). Parana: Caiobá, 30 June 1944, R. Hertel 1820 (S). São Paulo: Villa Prudente, Dec. 1917, H. Leuderweldt 1003 (GH, NY); In campis inter St. Paulo et Jaguary, Jan. 1834, Riedel s.n. (US); In campis Ytú, Feb. 1834, Riedel & Luschnatt 2028 (Gh, NY, US).

Discussion:

Cassia chartacea, named for the unusually thin and obscurely veined leaflets, is based on a number of collections, showing considerable homogeneity in the typicalvariety, which were first recognized by inference as a taxonomic entity by Bentham, who cited Martius 1076 under C. uniflora, evidently adopted a different concept of that species than was intended by Sprengel. This is clear from Sprengel's type description of C. uniflora Spreng., in which C. lanceolata Pers., while listed as a possible synonym, is later in the same description regarded as agreeing with C. uniflora in with C. tetraphylla Desv. var. brevipes (Benth.) Irwin. Colladon's (1816) type description of C. persoonii similarly treats C. lanceolata as a synonym.

In his monograph of the genus (1871), Bentham placed C. lanceolata and c. persoonii in synonymy under C. uniflora, but without having seen the types for any of the  three names. Thus, it is clear that Bentham's concept of C. uniflora was not gained as a result of critical study of the specimens but rather from the wholly inadequate disgnoses of the authors mentioned. It is clear that C. uniflora and C. persoonii are based on the Lamarckian specimen which typifies C. lanceolata; synonym of C. uniflora and C. persoonii, the material at hand requires separate documentation  as C. chartacea.

Careful study of material assignable to C. chartacea has shown that in 3 areas in Minas Gerais and southern Goias characters of this species tend to approch those of C. langsdorffii Kunth var. parvifoliola Irwin. In specimens from the first of these areas, southern Serra do Espinhaço, from Serra do Cipó northward to the vicinity of Diamantina, leaflets are often smaller, more apiculate, firmly membranaceous or subcoriaceous, the pedicels up to 0.7 mm thick in fruit, and the petiolar gland frequently long and somewhat stipulate. Material from the mountains immediately east of Belo Horizonte, i.e. from Itabirito to Ouro Preto, differs from the more northerly varient in having leaflets more nearly the size of those in the typical C. chartacea, but with longer stipules, very like those of C. langsdorffii var. parvifoliola. The third "region" is much less well defined and, judging from the few specimens now available , may not be a descrete region but simply a collection of isolated localities where sympatric hybridization and consequent introgression has occurred. These variants, from western Minas Gerais (Patos de Minas, Serra do Caracól) and southern Goias (Chapada dos Veadeiros), are similar in having even larger stipules, i.e. up to 1.4  cm long, unilaterally puberulent pedicels about as long as the stipules in fruit, and subsessile petiolar glands ca. 0.5 mm broad. Although both C. langsdorffii var. parvifoliola and the typical C. chartacea are sympatric in São Paulo, there are no known intergrades from that state. However, in lieu of actual field knowledge of the populations from which the above described specimens were obtained, it is felt that formal recognitionshould be deferred until the central Brazilian region becomes better known.

A forth varient, found on the savannas of bahia, Minas Gerais, São Paulo, and Paraná, is distinctive in its low, decumbent, ramose habit, its smaller but still membranaceous leaflets, and its narrower stipules. Because the taxonomy of the Xerocalyx species is relatively uncomplicated south of Minas Gerais and because of the apparent stability of this varient, it will be dealt with separately as C. chartacea in other respects, and is therefore included here.

Distribution:Brazil South America| Minas Gerais Brazil South America| Goiás Brazil South America| São Paulo Brazil South America| Pernambuco Brazil South America| Paraná Brazil South America|