Senna surattensis

  • Title

    Senna surattensis

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Senna surattensis (Burm.f.) H.S.Irwin & Barneby

  • Description

    2.  Senna surattensis (N. L. Burman) Irwin & Barneby, comb. nov. Cassia surattensis N. L. Burman, Fl. Indica 97. 1768—"Senna surattensis Garzin [=Laurent Garcin] herb."—Holotypus, originally labelled ‘Cassia sumatrensis’ but the epithet corrected in an old hand to ‘surattensis G (hb. Burman. annotated as typus by K. Larsen, 1978)!—Wrongly equated by Colladon, 1816, p. 105, with Cassia auriculata, and by DeCandolle, 1825, p. 495, with C. glauca and illegitimately reduced to it; restored by Merrill, Philip. J. Sci. 19: 353. 1921 but wrongly applied by De Wit, 1955, p. 269 and consequently by several modern writers, to our S. sulfurea.

    Cassia fastigiata Vahl, Symb. Bot. 3: 57. 1794.—"Habitat in India orientali. KONIG."—Caret in hb. Vahl., C!, but the protologue decisive and referred by Vahl himself (ms., C) to Cassia glauca.—Listed by Bentham among many synonyms of Cassia glauca, this name was overlooked by De Wit, 1955.

    Cassia suffruticosa Roth, Nov. sp. pi. 213. 1821.—. . communicavit celeber HEYNE ex India Orientali."—Collected presumably by Konig, no typus found, but the protologue decisive. Referred by Bentham, 1871, p. 555, to synonymy of C. glauca.—C. glauca var. koenigii Kurz, J. Asiatic Soc. Bengal 45(2): 284. 1876. C. glauca var. suffruticosa (Roth) Baker in Hooker f., Fl. Brit. Ind. 2: 265. 1878. Psilorhegma suffruticosa [sic] (Roth) Britton ex Britton & Rose, N. Amer. Fl. 23(4): 255. 1930. Cassia surattensis subsp, suffruticosa (Roth) K. & S. Larsen, J. Nat. Hist. Siam. Soc. 25(3-4): 205. 1974. Cassia surattensis var. suffruticosa J. R. Sealey ex Isely, Mem. N.Y. Bot. Gard. 25(2): 129, 209. 1975, illegitimate because the varietal epithet koenigii prior.

    Senna speciosa Roxburgh, Fl. Ind. 2: 347. 1832.—". . . only found in gardens . . ."—Lectotypus, cult, in India, K. (hb. Benth.)!—Equated with C. suffruticosa by Wight & Arnott, Prod. Fl. Pen. Ind. 1: 289. 1834.

    Cassia surattensis sensu Bentham, 1871, p. 55, ex parte; Symon, 1966, p. 100, quoad descr.; Chun & Chang, Fl. Hainanica 2: fig. 421. 1965; Walker, Fl. Okinawa and s. Ryuku Is. 546, fig. 74. 1976.

    Cassia suffruticosa sensu Wight & Arnott, 1834, l.c. supra; Bentham, Fl. Austral. 2: 285. 1864; Iconogr. Cormophyt. Sinic. 2: fig. 2413. 1972. C. glauca var. suffruticosa sensu Gagnepain in Lecomte, Fl. Gen. de l'Indochine 2(2): 160. 1913; Gamble, Fl. Presidency Madras 1(3): 403. 1919; V. Singh, Bull. Bot. Surv. India 18(1-4): 91. ("1976") 1979.

    Like closely related S. sulfurea except for more numerous, smaller lfts, smaller brachystylous fls and shorter, short-stipitate pod, the young growth and almost always the dorsal face of lfts pilosulous with ascending or subappresed, often lutescent hairs to 0.2-0.45 mm, the lfts strongly bicolored, glaucous beneath, the mature inflorescence commonly corymbose-paniculate toward the end of densely leafy annotinous branchlets.

    Stipules (of S. sulfurea) 4.5-13 x 0.5-1.4 mm.

    Lvs 8-18 cm; petiole 2-3.5(-4) cm; rachis (4-)4.5-10.5 cm, its longer interfoliolar segments 9-15(-17) mm; glands between 1-3 proximal, commonly only between first or first and second pairs of lfts, stipitate, slenderly or stoutly claviform, in profile 1-2.4 x 0.3-0.7 mm; lfts 6-10 pairs, strongly accrescent and proportionately narrower distally, obovate, elliptic-obovate or broadly oblanceolate obtuse, the longest (distal or penultimate) pair (2-)2.5-4.5(-5) x (0.8-) 1-1.8(-2) cm, 2.2-3 times as long as wide, veined like those of S. sulfurea, but the major camptodrome secondary veins only 6-8(-9) pairs.

    Peduncles (2.5-)3-8 cm; racemes shortly densely 5-17(-21)-fld, the axis becoming 4-25 mm; bracts thinly herbaceous ovate- or broadly lance-acuminate (2-)2.5-7 x (1-) 1.2-2.6 mm, persistent into anthesis, then deciduous, the lowest occasionally subtended on one side by a claviform gland; pedicels at and after anthesis 16-25 mm; outermost sepal 3-4(-4.4) mm, innermost one 5.5 7.5(-8) mm; corolla of S. sulfurea but on average smaller, the longest petal (16 ) 18-24 mm; androecium of S. sulfurea, 9 filaments 0.7-2 mm, that of the centric abaxial stamen 1.5-3.5 mm, anthers of 9 stamens 4-5.2 x 1.1-1.5 mm, that of the centric abaxial one (4.5-)5-6.5 x 1.1-1.6 mm; style 1.5-3 mm; ovules (18-)22-30.

    Stipe of pod 5-7 mm, the body 7-10 x 1.1-1.5 cm, in other respects not different from that of S. sulfurea; seeds essentially similar but a trifle smaller, 4.9-5.9 x 2.5-3.4 mm, the areole 2.7-3.6 x 1.2-1.8 mm.—Collections: 27.—Fig. 10 (androecium), 13 (pod, seed).

    Of obscure origin, thought by Bentham (1864) to be native to coastal n. Australia (N. Terr, and offshore islands) but characterized by Symon (1966) as probably an old introduction there, in India, Burma, Indochina, Philippine Is. and Malaysia planted in parks, gardens and temple yards, whence locally adventive, of uncertain status on the Caroline and Society Is., a common locally weedy ornamental on Oahu in Hawaii; cultivated in subtropical United States and locally established in s. peninsular Florida (Dade Co.); in West Indies cultivated before 1826 on St. Vincent, Windward Is., and latterly in Puerto Rico.

    For comment see above under S. sulfurea. We gratefully acknowledge the help of Mrs. A. Fox Maule, curator of type specimens at the Botanical Museum in Copenhagen, for help in interpretation of C. arborescens and C. fastigiata and for supplying us with copies of Vahl’s notes on these species, no longer represented by specimens in his herbarium.