Senna pallida var. cordillerae

  • Title

    Senna pallida var. cordillerae

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Senna pallida var. cordillerae H.S.Irwin & Barneby

  • Description

    177o. Senna pallida (Vahl) var. cordillerae Irwin & Barneby, var. nov., a var. pallida late per Americae Centralis regionem inferiorem dispersa seta petiolari in glandulam transformata, foliolorum venatione simpliciter subtillime penninervia (nec dorso reticulata), legumine latiori 5-6.5 (nec 3-4.5) mm lato, seminumque areola 1.8-2.2 (nec 0.5-0.8) mm diam valde diversa; differunt varietates mexicanae seta glanduliformi praeditae lemniscata legumine longissimo (17-26 cm), macdougalliana foliolis majoribus 3-6 (nec 2-4) cm usque longis utrinque nec dorso tantum glaucescenti-pallidis, et trichocraspedon foliolis margine exi- mie revolutis necnon utraque facie prominule venulosis.-COSTA RICA. Alajuela: buissons au bord du rio Virilla, XII. 1895 (fl, fr), A. Tonduz 9824 distrib. Donnell Smith 7007.-Holotypus, US; isotypi, F, K, NY, US.

    Cassia pallidior Rose, J. Wash. Acad. Sci. 17: 167. 1927, pro parte, quoad pl. costaricens, cit., exclus. typ.

    Amply leafy arborescent shrubs 1.5-5 m with pliant, bluntly angulate, commonly plagiotropic hornotinous branchlets, the thin-textured foliage strongly bicolored, the lfts dull dark green and glabrous above, pallid-glaucescent and at least along costa thinly strigulose beneath, ciliolate, the inflorescence of 2-fld racemes axillary to coeval lvs and shorter than them, rarely 2 together on a short leafless axillary branchlet.

    Stipules (caducous, little known) falcately linear-acuminate 4.5-8 x 0.5-1.5 mm.

    Major lvs 8-16(-18) cm; petiole 10-20(-24) x 0.6-1.1 mm, a little more or less than twice as long as first interfoliolar segment of rachis; rachis 6-11 cm, the terminal seta (caveat: sometimes deciduous, often eaten) transformed into an ellipsoid gland; petiolar gland 1 between proximal pair, sessile or shortly stipitate, 1.7-2.5 x 0.6-0.9 mm; lfts (8-)9- 12(- 13) pairs, oblong-elliptic or -oblanceolate obtuse mucronate, the larger pairs (18-)20-42 x 6-14 mm, 2.5-3.3 times as long as wide, the simply pinnate venation of (5-)6-8 pairs of major camptodrome secondaries immersed or almost so above, delicately raised or merely colored beneath.

    Peduncles (8-) 10-21 mm; pedicels 17-23 mm, in fruit bent well above middle; long sepals 6.5-8.5 mm, long petals 21-30 mm; filaments glabrous or puberulent, all free, those of 4 median stamens 1.2-2, of 3 abaxial ones 2.7-4.5 mm; anthers of 4 median stamens 4-5.2 mm, obliquely truncate, each tubule conic-pointed distally, the very short declined beak lateral, those of 3 abaxial ones strongly incurved, the body 6.5-7.5 mm, the erect beak 2.6-3.1 mm.

    Stipe of pod 5.5-8.5 mm, the body (8-) 11-17 x 0.5-0.65 cm, the papery nigrescent valves continuous in age, simply expressed over seeds, the interseminal septa 2.5-4 mm distant; seeds compressed-obovoid 3.2-3.5 x 1.7-2 mm, the testa brown sublustrous, the areole 1.8-2.2 x 0.8-1.2 mm.-Collections: 20.

    Margins and openings in seasonally moist forest, persisting in pasture thickets, along hedges and on stream banks, 850-1525 m, locally abundant on both slopes of Cordillera Central in San Jose and Alajuela, Costa Rica.-Fl. VIII-II, sporadically through the year.

    In the flora of Costa Rica there are two abruptly distinct biflorous Interglandulosae, one in the seasonally dry lowlands of Guanacaste and Puntarenas, the other in the central highlands of Alajuela and San Jose. The former has mostly 4-7, rarely 9 pairs of leaflets reticulate beneath and a pod 3-4.5 mm wide sharply raised over the seeds in decussate pyramids; it is the widespread var. pallida, of which the seeds have an areole less than 1 mm diam. The highland senna described above as var. cordillerae has mostly 9-12 pairs of simply penniveined leaflets, pods 5-6.5 mm wide simply mounded over the seeds, and an areole about 2 mm long. It differs further from other highland Central American varieties of S. pallida (all allopatric northward) in the glandiform seta between the distal pair of leaflets. In this last feature it resembles the Mexican vars. lemniscata, macdougalliana and trichocraspedon, of which the diagnostic characters are brought out under the next three varieties following.

    The protologue of Cassia pallidior Rose, even though the peculiar seta went unnoticed, is based largely on material of var. cordillerae, but the specified typus represents glabrate var. pallida.