Stilbanthus scandens Hooker

Ranjan, Vinay, Kumar, Anant & Krishna, Gopal, 2023, Recollection, typification, and taxonomic notes on Stilbanthus scandens (Amaranthaceae), Phytotaxa 589 (2), pp. 209-212 : 209-212

Stilbanthus scandens Hooker filius (1879: 67).

Lectotype (designated here):— INDIA. “Hab. Sikkim. Regio subtrop. Alt. 4−6000 ped”, Hooker s.n. (CAL0000217508!) ( Fig. 1 ).

Description ( Fig. 2 ):— Large gigantic woody climber with pendulous branches; stems quadrangular, grooved, sparsely pubescent, dense at swollen nodes. Leaves opposite, ovate-elliptic, 5.3–11.8 × 2.5–5.2 cm, base oblique-cuneate to equally cuneate, margins not prominently crenate or entire, apex acuminate, sparsely pubescent above, less pubescent only on nerves beneath; veins 5–7 pairs, prominent; petioles 0.7–1.5 cm long, sparsely pubescent. Flowers in densely flowered spikes; spikes pendulous, 2.0– 8.5 cm long, in terminal spreading trichotomously branched panicles and axillary, sometimes subtended by small foliaceous bracts; peduncles 2.0– 4.5 cm long, densely pubescent. Perianth segments ovate-lanceolate, 8–9 × 3.5–4.0 mm, accrescent, whitish woolly at apex, scarious, striated, midvein not prominent; perianth bracts 3.0–4.0 × 2.0– 2.5 mm, ovate, hairy at apex, midvein extended to mucronate, scarious; bracteoles 1.8–2.0 × 1.0– 1.5 mm, ovate, scarious. Stamens 5; filaments slender, 5.5–6.0 mm long, hairy up to 1/3 of length, connate at base; anthers oblong, c. 1 mm long, 2-celled; staminodes membranous, long ligulate lacerate irregularly. Ovary elliptic-oblong, 2.0– 2.5 mm long, compressed, densely hairy of penicillate at apex, otherwise smooth; style filiform, 4.5– 4.5 mm long, glabrous; stigma capitate. Fruit oblong, 3.0– 3.2 mm long, indehiscent, with a circular rim at apex, smooth except apical part.

Phenology:— Flowering and fruiting times September–December

Habitat:— Grows in the valleys of warm broad-leaved subtropical forests, 900–2100m.

Distribution:— INDIA: Arunachal Pradesh, Nagaland, Sikkim, West Bengal; BANGLADESH, BHUTAN, CHINA, MYANMAR.

Lectotypification of the name:— The monotypic genus Stilbanthus was validly described by Hooker filius (1876: 67) by the publication of the species Stilbanthus scandens from “Forest of the Sikkim Sikkim Himalaya at elevation of 4–6000 ped; Herb. Griffith, J.D.H. [Jospeh Dalton Hooker] Fl. August, September”. These Griffith’s and Hooker’s gatherings represent at least two syntypes according to the Art. 9.6 of Schenzhen Code (hereafter reported as “ICN”; Turland et al. 2018). Moreover, Hooker filius (1876) published an illustration (”PLATE 1286”; image available at https://www.biodiversitylibrary.org/item/ 54432#page/168/mode/1up) which is also an original material for the name (Art. 9.3 of ICN). We traced five syntypes, of which three were collected by Hooker filius [CAL0000217508, L1691279 (image at https://bioportal.naturalis.nl/specimen/ L.1691279/term= Stilbanthus +scandens&from=0), C10005461 (image at https://plants.jstor.org/stable/viewer/10.5555/al.ap. specimen.c10005461?loggedin=true),] and two by Griffith [K000848078 (image at http://apps.kew.org/herbcat/getImage. do?imageBarcode=K000848078) and CAL0000217104). Griffith’s collections (K000848078 and CAL0000217104) include the script (stamped) “HERBARIUM BENTHAMIANUM 1854”, so confirming that Hooker filius seen them. Note that the herbarium and types of Joseph Dalton Hooker (son of William Jackson Hooker) are mainly preserved at K (HUH-Index of Botanists 2013 +), where strangely we did not find any Hooker’s collection (but only a Griffith’s one). We here designate CAL0000217508 as the lectotype of the name Stilbanthus scandens : it matches the protologue, is well preserved, and corresponds to the correct concept of the species (see e.g., Bao et al. 2003, Mao et al. 2017, Paul & Chaudhury 2019).

Taxonomic notes:— Hooker filius (1876: Pl. 1286) illustration does not exactly correspond to the original description. The shown staminodes is filiform with plumose apex while those are thin membranous and tored at random heights in to filiform appendages or irregularly lacerate. Apart from this, stamens are also equal to staminodes in studied specimens which is contradictory in figure. The shown ovary is glabrous at apex while it is found bearded or pencillate all around the style base. Hence, authors are discussing first time these errors to avoid confusion on identity, circumscription and illustration mismatch.

Other specimens examined:— INDIA. Arunachal Pradesh , Kameng, 17 May 1958, Panigrahi 15695 (ASSAM); Tirap , 22 August 1958, Panigrahi 14549 (ASSAM) . Nagaland , Naga hills, April 1936, Bor 17662 (ASSAM); Dzuko valley, Fakhanca hills, 14 April 2000, 2400m, Mao & Gogoi 111280 (ASSAM) . Sikkim, 19 July 1881, King s.n. (CAL, 2 sheets); King 986; 23 November 1908, Craib 264; 25 October 1868, Kurz s.n. (CAL); November 1875, Kuntze 6849 (NYBG02592301 Image!); ibidem (NYBG02496900 Image!); Rungbee, 6,000ft, 08 August 1923, Cave s.n. (A01539283 Image!); Rungbee, 6000ft, 8 August 1923, Cave s.n. (E01153443 Image!). Darjeeling, Kalimpong district, Neora Valley National Park , Kolbong to Kolakham, 27°05’39.5”N 88°41’16.0”E, 1881.75m, 23 September 2016, Ranjan, Krishna & Kumar 77126 (CAL); Cowan s.n. (E01153444 Image!). MYANMAR (Burma). Mt. Victoria , 1924, Cooper 6033 (E00992615 Image!), Paypal Bunglow, 6-7000ft, 19 September 1912, Lace 38 (E00992616 Image!) . CHINA. Yunnan, 4000ft, 1912, Forrest 9404 (S06-5050 Image!) . NEPAL. Pheriche , 13,500ft, 30 July 1966, Banerji s.n. (A01539281 Image!) .

Figures

FIGURE 1. Lectotype of the name Stilbanthus scandens (CAL0000217508!).

FIGURE 2. Stilbanthus scandens: (A) Flowering twig; (B) Flower; (C) Bract; (D) Bracteole; (E) Tepal; (F) Ovary; (G) Stamen; (H) Staminode.