Cassia fragilis

  • Title

    Cassia fragilis

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Cassia fragilis H.S.Irwin & Barneby

  • Description

    121.  Cassia fragilis Irwin & Barneby, sp. nov., omnium partium glabritie, petiolo communi gracillimo flexuoso, foliolisque ellipticis basi cuneatis margine glanduloso-crenulatis C. dentatam Vogel simulans, sed foliolis 3-4 (nec 1-3)-jugis obtusis et emarginatis (nec acuminatis acutisve) haud vel vix asymmetrice incurvis, utrinque opacis eglandulosis (nec superne nitidis inferne resinoso-punctulatis), pedicelliis abbreviatis (1.4-2 nec 4.5-8 cm longis), necnon floribus multo minoribus (sepalis 8-9 nec 14-20 mm longis) manifeste distincta. — BRAZIL. Goias; campinhas, Pinguella, fl + fr jun, VIII.12 von Lutzelburg 1552. — Holotypus, RB (no. 6062).

    Shrubby or possibly arborescent, of unknown habit and stature but the slender, livid or nigrescent, resinous branchlets perhaps pendulous, glabrous except for a few livid glandular verrucae on the lf-stalks, stems and pedicels, and scattered pallid pustules (representing setules without a shaft) in the inflorescence and pod, the foliage olivaceous concolorous, scarcely viscid, the lfts crenulate by impressed glands but glandless on both surfaces.

    Stipules appressed to stem, similarly resinous, narrowly triangular-subulate, 1-1.5 mm, deciduous.

    Lvs apparently pendulous on slender pliant petioles, 6-12 cm; pulvinus moderately dilated, when dry wrinkled, pallid or purpurascent, 2-2.5 mm; petiole (2.5-)3-4.3 cm, 0.5-0.7 mm diam, narrowly grooved ventrally; rachis 2.5-5.5 cm; lfts 3-4 pairs, distant, tilted forward and somewhat edgewise on subcylindric, pallid, when dry wrinkled, sparsely verruculose pulvinule 2-2.5 mm long, of nearly equal size or the distal pair slightly longer, in outline elliptic-oblanceolate, obtuse or emarginate, bluntly minutely gland-mucronulate, 20-44 x 8.5-15 mm, at base asymmetrically cuneate, the margins plane, thickened, finely crenulate by impressed livid glands, the blades sub- coriaceous, on both sides brownish-olivaceous, dull, minutely pallid-papillate, the subcentric straight or slightly incurved midrib and 5-7 pairs of secondaries immersed or barely prominulous above, beneath a trifle more prominent.

    Inflorescence of few, shortly and loosely 2-6 flowered racemes axillary to leaves of terminal branchlets, axis 1-4 cm, the fls immersed in foliage and the one fl at anthesis at or above level of succeeding bud; bracts thick-textured, triangular-subulate, ± 1.5 mm, livid and verruculose, caducous; pedicels slender, ascending, 14-20 mm, compressed, bracteolate 2-6 mm below calyx; bracteoles resembling bracts, scarcely smaller, subpersistent; buds ovoid-ellipsoid, obtuse, pallid-pustulate; sepals firm, elliptic to obovate-elliptic obtuse, 8-9 x 2.5-4.5 mm; petals (scarcely known) yellow, up to ± 14 x 8 mm; ovary pustular; ovules 5-7.

    Pod (young) ± 30 x 6 mm, the nigrescent valves glutinous, thinly pustulate.

    Habitat not recorded and range little understood, to be expected in cerrado or at margin of gallery forest on the crest or either slope of Espigao Mestre along the Goias-Bahia boundary near 10° 30'-12° S. - Fl. V-VIII.

    In general aspect the two known collections of C. fragilis are quite suggestive of C. dentata, being fully glabrous except for rudimentary setules in the inflorescence and having similar pliant petioles and narrow, crenulate leaflets cuneate at base; but the more numerous (3 or 4, not 1-3) pairs of leaflets are obtuse to emarginate, not acuminate at apex, straight or only obscurely incurved, and dull on both sides, not glutinous above and resin-dotted beneath. The position and length of the short, few-flowered racemes are alike in both species, but the flowers of C. fragilis are smaller and borne on much shorter pedicels up to 2 cm, not 4.5-8 cm long. No habital data accompany the specimens so that it is only possible to guess at the habit of the plant from the appearance of the branchlets, which are however quite similar in appearance to those of C. dentata. In both specimens many of the leaves and their component leaflets have disjointed after drying, a feature which suggested the epithet fragilis.

    Neither of von Lutzelburg's localities has been identified with certainity. The "Millionth'' map shows a Sao Jose do Duro situated on the west slope of Serra do Duro near 11° 20' S., 46° 30' W, that is in the northern Serra Geral de Goias between the present Dianopolis and the Bahia state line; but no probable Pinguella, which should be close by, has been traced. Nevertheless, the species should be sought in Serra Geral along the Goias-Bahia boundary.