Chamaecrista mucronata

  • Title

    Chamaecrista mucronata

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Chamaecrista mucronata (Spreng.) H.S.Irwin & Barneby

  • Description

    12. Chamaecrista mucronata (C. Sprengel) Irwin & Barneby, comb. nov. Cassia mucronata C. Sprengel, Syst. veg. ed. 16, 2: 341. 1825.—"Brazil."— Holotypus, labelled "Brasilia: Sellow" and ticketed by Sprengel "Cassia mucronata. Brasil. Otto," B (hb. Spreng.) = F Neg. 1712! Vogel, 1837, p. 58, expanded the data to "In Brasilia: Sellow leg. pr. Villa Rica, ad Itambe aliisque locis."—Presumed isotypus, M!

    Cassia arrojadoana Harms, Notizbl. Bot. Gart. Berlin 8(80): 715. 1924.—"Brasilien: Bahia, Rio de Contas, casa de Pedra, Campo (Ph. von Luetzelburg n. 8. 1913)."—Holotypus, †B; neotypus, Luetzelburg s.n., coll. VII. 1913 (fl), M!

    Cassia mucronata sensu Bentham, 1870, p. 171; 1871, p. 575.

    Slender prostrate or obliquely ascending shrubs at anthesis 0.5-1.5 m, with brown, ± lenticellate twiggy trunks and densely leafy, divergent or subpendulous hornotinous branchlets, pilosulous with widely ascending or divaricate gray hairs up to 0.4—0.7 mm, the stems and lf-stalks densely, the concolorous foliage more thinly so, the lfts sometimes glabrous above and glabrescent beneath, always ciliolate.

    Stipules erect firm lanceolate to triangular, 1.5—4.5 mm, at symmetric base 0.4-1 mm wide, (l-)3-5-nerved, persistent but becoming dry and fragile.

    Lvs (1.5-)2-4(-4.5) cm, very shortly petioled, the expanded blade ovate in outline, lf-stalk 1—3 cm, the petiole (1.5—)2—5 mm, the rachis narrowly wing-margined, the wing-segments not dilated upward; petiolar glands 1—4, inserted immediately below pairs of lfts, the lowest round or nearly so, (0.5-)0.6-1.3 mm diam, squatly short-stalked or sessile, the obconic stalk or pediment 0.3—0.7 mm tall, lfts 2—5(—6) pairs, slightly diminished upward, subsymmetricaUy elliptic-obovate to elliptic- or oblong-oblanceolate, 10—26 x 4—12(—14) mm, semicordate at oblique base, at obtuse or emarginate apex contracted into a stiff but non-vulnerant erect or retrocuryed mucro (0.2-)0.4-1.2 mm, the chartaceous blades subequally venulose on both faces or more prominently so beneath, 4—6-nerved from pulvinule by the straight, slightly displaced midrib with 2-4 primary veins on its proxima and 1 on the distal side, the midrib penniveined with 2—5 major and sometimes weaker intercalary secondaries.

    Peduncles exactly axillary, 0.5-2.5 mm, 1-2-fld; bracts and bracteoles resembling stipules, slightly smaller; pedicels ascending (1.2—) 1.4—2.4 cm; buds ovoid-acuminate, finely pilosulous or glabrescent; sepals subpetaloid, elliptic- or ovate-acuminate, 11—14 mm; petals yellow, the 4 similar ones obovate- or oblong- cuneate up to 14.5—20 mm, the dimidiate fifth one 20—23 mm; stamens 10, the anthers yellow, the long ones 5—7.5 mm; ovary appressed-pilosulous; style linear 7-8.5 mm, glabrate beyond middle; ovules 10-14.

    Pod erect, linear-oblong, 55—70 x 7-8.5 mm, the castaneous nigrescent valves finely puberulent; seeds 4-4.8 x 2.6-3.8 mm, the testa dull rufous-brown or blackish, deeply lineolate-pitted.—Collections: 34.

    Rocky hills and outcrops, mostly on schistose or sideritic ("canga") soils, locally plentiful at 1150-1600 m on the crest and e. slope of Sa. do Espinhaço from Itambé do Mato Dentro s. to Congonhas do Campo and Itacolomí near Ouro Preto (±19°30'-20°30'S) in s.-centr. Minas Gerais, e. (disjunctly?) to w.-centr. Espírito Santo (Reserva de Linhares); distantly disjunct on the headwaters of Rio Paraguaçú (? and Contas) in Chapada Diamantina (±12°30'-13°30'S), s.-centr. Bahia; a report from Maranhão (Bentham, 1871, p. 575) was based on specimens of Ch. pascuorum collected by Martius at Rio Itapicurú.—Fl. VII-IV.