Cassia chartacea var. tenuicaulis H.S.Irwin

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

Scientific Name

Cassia chartacea var. tenuicaulis H.S.Irwin

Type

Holotype (US): Brazil, São Paulo, "in campis arenosis, Araracoara." Riedel 2198. The label of the type specimen bears the date 1834, but since Riedel ceased collecting in Brazil in 1825, it is believed that the correct date is 1824.

Description

Latin Diagnosis - Planta decumbens ramosior suffruticosa aut fruticosa ad 0.5 m alt., saepe penicillatim fasciculata ad 1 m lat. Caules tenues, iuvenes saepe flexui glabri puberuleniesve. Stipulae adpressae persistentes lanceolato-cordatae, longo-acutae aut -acuminatae, 2.1-6.8 mm long., 1.1-1.9 mm lat., glabrae, ad basim interdum ciliolatae, integrae. Petioli tenues, 1.1-2.3 mm long., canaliculo aclaxiali puberulente, superficie abaxiali glabra puberulenteve, raro brevi-pilosa; rachis aeque longa ac petiolus aut 0.5 brevior, interdum sursum arcuata, terminaliter aristulata. Gians 1 plerumque scutellata, 0.2-0.4 mm lat., sessilis subsessilisve, raro brevi-stipitata, interdum depressa et non perspicua. Foliola bijugata, pari superiore plerumque longiore, per pulvinulum minutum arcuatum atrum brunneumve sessilia, lanceolato- aut oblanceolato-oblonga, paululum obliqua, recta aut laminis superioribus divergentibus, glabra membranacea papyriferave, 0.4-1.4 cm long., 2.1-3.1 mm lat., saepe cinereo-viridia; margines integri, apice obtuso rotundaiove. Flores axillares plerumque singulares; pedicelli recti glabri aut rarius in linea puberulentes, 1.5-2.8 cm long., c. 0.3 mm crass, dum Horentes, usque ad 3.7 cm long., 0.5 mm crass, dum frugiferentes; bracteae 2, lanceolatae aut anguste ovaiae, 1.5-1.9 mm longae, 0.5-0.9 mm lat.; bracteolae suboppositae remotaeve, lanceolatae, 1.7-2.3 mm long., 0.6-1.1 mm lat.; sepala lanceolata 7.8-11.0 mm long., 2.1-2.6 mm lat.; petala (lava, 8.9-13.5 mm long., 7.0-10.7 mm lat.; stamina flava: ovarium in margine aut omnino breve cinereo-pilosum. Siliqua anguste oblonga, 1.8—3.1 cm long.; 0.4—0.6 cm lat., plana aut quasi plana, in suturis glabra aut parce puberulens. Semina 8-14, levia dura brunnea atrave, paululum compressa 3.2-4.7 mm long., 0.7-1.2 mm lat.

Description - Decumbent, freely-branched subshrub or shrub to 0.5 m, frequently forming tufted clumps up to 1 m broad. Stems slender, often flexuous when young, glabrous or puberulent. Stipules lanceolate-cordate, long-acute or -acuminate, 2.1-6.8 mm long, 1.1-1.9 mm broad, glabrous, occasionally ciliolate at base. Petioles slender, 1.1-2.3 mm long, the adaxial groove puberulent, the abaxial surface glabrous or puberulent, rarely short-pilose; rachis 0.5-1.0 as long as petiole, sometimes arched upward. Gland 1, usually scutellate, 0.2-0.4 mm broad, sessile or subsessile, rarely short-stipitate, sometimes depressed and obscure. Leaflets bijugate, the superior pair usually longer, joined to rachis by a minute, arcuate, black or brown pulvinule, lanceolate- or oblanceolate-oblong, slightly oblique, straight or the superior blades divergent, glabrous, membranaceous or papyriferous, 0.4-1.4 cm long, 2.1-3.1 mm broad, often gray-green; apex obtuse or rounded. Flowers usually solitary; pedicels straight, somewhat flattened, glabrous or less commonly puberulent in a line, 1.5-2.8 cm long and ca. 0.3 mm thick in flower, up to 3.7 cm long and 0.5 mm thick in fruit; bracts 2, lanceolate or narrowly ovate, 1.5-1.9 mm long, 0.5-0.9 mm broad; bracteoles subopposite or remote, lanceolate, 1.7-2.3 mm long, 0.6-1.1 mm broad; sepals lanceolate, 7.8-11.0 mm long, 2.1-2.6 mm broad; petals 8.9-13.5 mm long, 7.0-10.7 mm broad; ovary marginally or wholly short gray-pilose. Pod narrowly oblong, 1.8-3.1 cm long, 0.4-0.6 cm broad, flat or nearly so, glabrous or sparsely puberulent on sutures. Seeds 8-14, slightly compressed, 3.2-4.7 mm long, 0.7-1.2 mm broad. Chromsome number: not determined.

Discussion

This taxon differs from the typical variety not only in its distinctive habit but also in its slender, wiry stems, the generally smaller foliar organs, and the often glabrous pedicels and fruit. Material from Parana tends to resemble that of the typical variety, while in São Paulo var. tenuicaulis is quite distinct.

Distribution

Distribution: Brazil, São Paulo and Paraná. Occurring mainly in savannas on sandy soils, from 900 to 2000 feet elevation.

Brazil South America| São Paulo Brazil South America| Paraná Brazil South America|