Strobocalyx mastersii B. Bhattacharjee, Lakshmin., S.K. Mukherjee & Av. Bhattacharjee, 2017

Bhattacharjee, Bandana, Lakshminarasimhan, P., Mukherjee, Sobhan Kumar & Bhattacharjee, Avishek, 2017, A new species of Strobocalyx (Asteraceae: Cichorioideae: Vernonieae) from India, Phytotaxa 299 (2), pp. 280-284 : 281-283

Strobocalyx mastersii B. Bhattacharjee, Lakshmin., S.K. Mukherjee & Av. Bhattacharjee , sp. nov.

‘ Vernonia mastersii Watt’ in sched.

Type:— INDIA. Assam: Getukai, 24 April 1895, G. Watt 11199 (holotype: CAL!, barcode CAL0000018787 ; isotype: CAL, barcode CAL0000026423! ) ( Fig. 1 ).

Diagnosis: — Strobocalyx mastersii is close to S. arborea (Buchanan-Hamilton 1823: 218) Schultz-Bipontinus (1861: 171) but differs in having shorter leaves which are up to 14 cm long (vs. up to 30 cm long in S. arborea ), 4-angled achenes 1.5–2.5 mm long which are devoid of any rib (vs. terete, 10-ribbed achenes 3–5 mm long in S. arborea ), inner pappus 4–5 mm long (vs. 6–10 mm long in S. arborea ). Strobocalyx mastersii is also similar to Monosis volkameriifolia but can be distinguished in leaves narrowly elliptic-oblong to ovate-oblong (vs. obovate in M. volkameriifolia ) with the abaxial surface densely tomentose throughout (vs. abaxial surface scabrous, pubescent or tomentose only along veins), florets shorter (7–9 mm long vs. 16–19 mm long in M. volkameriifolia ) with a shorter style (5–7 mm long vs. 13–15 mm long in M. volkameriifolia , including bifid style apices), achenes 4-angled (vs. terete 10- ribbed in M. volkameriifolia ) and pollens non-lophate (vs. lophate in M. volkameriifolia ).

Description:—Trees with rather terete branches. Leaves alternate; petiole 1–3cm long, densely tomentose; leaf blade narrowly elliptic-oblong to ovate-oblong, 6–14 × 2–5.5cm, obtuse at base, subacute to obtuse at apex, adaxially glabrous, abaxial surface densely tomentose throughout, hairs long, simple, uniseriate. Inflorescences somewhat sympodial, corymbiform, densely fulvous tomentose. Capitula with 5–10 florets. Involucres narrowly campanulate; phyllaries 4–5-seriate, ovate to ovate-oblong, 0.8–2 mm long, chartaceous, without median thickened shield, pubescent, obtuse at apex, outer short. Florets narrowly funnelform from near base, 7–9 mm long (including the projecting style and stigma); tube 3–4 mm long; lobes linear-lanceolate to narrowly deltoid, acute to shortly acuminate at apex. Stamens 5, syngenecious; anther ca. 2.5 mm long, narrowly sagittate; filament 1.5–2 mm long. Ovary 2–3 mm long; style 5–7 mm long (including bifid style apices) and a small basal node (knob like structure), upper shaft and branches with blunt sweeping hairs; stigmatic surfaces ca. 1.5 mm long on each branch of style. Achenes 4-angled, often grooved between angles, oblong-cylindric, 1.5–2.5 mm long, 0.7–1 mm wide (near apex), entirely glabrous or glabrescent at apical part; pappus of many long capillary bristles 4–5 mm long, with few shorter bristles at base ca. 0.4 mm long but not forming distinct outer series. Pollens non-lophate with crowded spinules.

Flowering & Fruiting:—April (in some related species flowering usually starts from January).

Distribution: — India (Assam, Meghalaya).

Additional specimens examined: — INDIA. Assam, Sibsagar, precise locality illegible, 1888, S.E. Peal s.n. ( CAL; barcodes CAL0000025838 , CAL0000025839 ) ; Meghalaya, Khasia, without precise locality, Coll.? ( CAL; barcode CAL0000025840 ) .

Note: —The achenes of the genus Strobocalyx are reported to be 5–10-angled ( Robinson et al. 2008: 29; Robinson & Skvarla 2010: 269), but in this new species the achenes are 4-angled. We have also tried to study the micromorphology of pollen under Scanning Electron Microscope from more than 125 years old specimens, but probably due to age, preservation or other factors the surface-ornamentation was distorted. However, the non-lophate nature and short, crowded spinules are evident even from the distorted pollens. Rediscovery of this species in the field is required to study the pollens and chromosomes in detail to confirm its generic placement as per the present concept of Vernonieae .

Figures

FIGURE 1. Strobocalyx mastersii B. Bhattacharjee, Lakshmin., S. Mukherjee & Av. Bhattacharjee: A. Holotype. B. Portion of the lower surface of a leaf. C. Involucre showing phyllaries. D. Floret. E. Stamens. F. Gynoecium. G. Cypsela with 4-angled achene. B–G: from the holotype (G. Watt 11199; CAL).