Senna pallida var. longirostrata

  • Title

    Senna pallida var. longirostrata

  • Author(s)

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Senna pallida var. longirostrata (Britton & Rose) H.S.Irwin & Barneby

  • Description

    177g. Senna pallida (Vahl) var. longirostrata (Britton & Rose) Irwin & Barneby, stat. nov. Peiranisia longirostrata Britton & Rose, N. Amer. Fl. 23(4): 264. 1930.-"Type from Solola, Guatemala, January 27, 1915, E. W. D. Holway 134."-Holotypus, US! clas to typus (fragm) + phototypus, NY!-Cassia longirostrata (Britton & Rose) Lundell, Phytologia 1: 214. 1937.

    Shrubs 1-3 m with deeply sulcate hornotinous branchlets, varying from glabrous below the always strigulose-pilosulous ovary to densely pilosulous up to the glabrous fl-buds, the vesture of stems and lf-stalks composed of stiff, spreading-ascending hairs up to 0.4-0.8 mm but the lfts either pubescent on both faces or only beneath, the mature inflorescence corymbosely or virgately paniculate.

    Stipules linear-attenuate or narrowly linear-oblanceolate 5-15 x 0.4-1 mm.

    Major lvs 6-13 cm; petiole 2-3.4(-4) cm, at middle (0.5-)0.6-1(-1.1) mm diam, (2-)2.3-5 times as long as first segment of rachis; gland between proximal pair of lfts sessile or stipitate (1-) 1.4-3(-3.5) mm, the stipe when present either glabrous or pilosulous, the body 0.4-1 mm wide; lfts up to 6-9 pairs, accrescent upward along rachis, the distal pair largest, obovate, oblong-obovate or oblanceolate obtuse or deltately subacute 18-35 x (7-)8-14 mm, 1.8-3 times as long as wide, the simply pinnate venation of (4-)5-7(-8) pairs of camptodrome and some few faint intercalary secondary veins immersed and scarcely or not perceptible above, beneath either finely prominulous or immersed and discolored, tertiary venulation essentially 0.

    Peduncles (4-)8-22 mm; racemes 2(-4)-fld, the axis 0-1.5(-4) mm; pedicels 10-21 mm; long sepals (6-)6.5-9 mm; long petals (16-) 18-21 mm; filaments glabrous or pilosulous, free to base, those of 4 median stamens 0.9-1.8 mm, those of 3 abaxial ones 3-5.5 mm; anthers of 4 median stamens 3.2-5.3 mm, bluntly truncate, the lateral beak not over 0.4 mm, dehiscent by parallel pores, those of 3 abaxial ones 5-7 mm, contracted into beak 1.6-2.8 mm; style 1.7-2.5 mm.

    Stipe of pod 3-5 mm, the body 6.5-9.5 x 0.4-0.5 cm, the valves simply mounded over the seeds, the interseminal septa 1.5-2 mm apart; seeds not seen ripe, but the areole small, <1 mm diam.-Collections: 24.

    Thickets and brushy hillsides in oak-pine, cypress- and mixed forest, (1200-) 1400-2000 m, scattered through the mountains of Guatemala from s. Huehuetenango s.-e. to Jalapa (±89o30'-91°30').-FI. XI-II.

    Due to great superficial variation in pubescence and in outline of leaflets var. longirostrata is difficult to characterize neatly. It is closely related to vicariant and partly sympatric var. quiedondilla and resembles it in the relatively long petioles, but differs in the fewer leaflets accrescent upward along the rachis, the distal pair largest, and in the narrow pod and (presumably) smaller seed with smaller areole. Both leaflets and pods of var. longirostrata resemble those of lowland var. pallida except that the leaflets are simply penniveined, as in other highland varieties, and not reticulate; and the petiole is actually and relatively longer, 2-5, not ±1-2 times as long as the first segment of the rachis. The rarer var. tuerckheimiana, the third form of S. pallida found in the Guatemalan highlands at the same elevations and in the same latitudes, resembles pubescent var. longirostrata at anthesis, but has the broad pod, large seeds and numerous (10-13-jugate) leaflets of var. quiedondilla combined with the short petiole of var. pallida.

    The species Peiranisia longirostrata was described by Britton & Rose from a fragmentary specimen and contrasted in North American Flora with P. oxyadena, P. shaferi and P. robiniifolia, all distantly allied. The report in the protologue from Veracruz was based on a specimen of pubescent var. quiedondilla (Purpus 2342), mentioned under the latter heading. Despite the epithet, the beak of the long anthers is not exceptionally long in the context of either S. pallida, sens, lat., or of the whole series Interglandulosae.