Leptomischus flaviflorus Hareesh, L.Wu & M.Sabu, 2017

Hareesh, Vadakkoot Sankaran, Wu, Lei & Sabu, Mamiyil, 2017, Leptomischus flaviflorus (Rubiaceae), a new species from India, Phytotaxa 332 (1), pp. 88-92 : 90

Leptomischus flaviflorus Hareesh, L.Wu & M.Sabu sp. nov. ( Fig. 1 )

Similar to L. primuloides and L. modestus , but differs from the former by stems erect glabrous with 3.5–5 cm long internodes (vs. decumbent, pilosulous with 0.5–1 cm long internodes), leaf midribs dorsally glabrous (vs. puberulous), stipules glabrous (vs. pilosulous), bracts pubescent (vs. pilose), calyx 3/4 th length of the corolla (vs. 1/3 rd length), calyx lobes shorter than tubes (vs. longer than tube) and flowers homostylous (vs. heterostylous); it differs from the latter in its leaf midribs dorsally glabrous (vs. puberulous), bracts pubescent (vs. glabrous), calyx 3/4 th length of the corolla, ciliate (vs. nearly as long as the corolla), calyx lobes shorter than tubes(vs. longer than tube), corolla pubescent and corolla lobes with acute apex (vs. glabrous, corolla lobes with apiculate apexes).

Type:— INDIA. Arunachal Pradesh: Changlang district, near Namdang, 24 May 2016, V. S. Hareesh 149329 (holotype, CAL).

Erect herb, 15–60 cm tall; stem un-branched, terete, glabrous, green; internodes 3.5–5 cm long. Stipules entire, acute to acuminate at apex, glabrous, persistent, green; basal stipules orbicular, 14–16.5 × 15–17 mm; distal stipules broadly ovate, 20–22 × 27–30 mm. Petioles 3–7.5 cm long, terete, glabrous, pale green; leaf blades elliptic to elliptic-lanceolate, 20–32 × 8.5–15 cm, attenuate at base, acute to acuminate at apex, margin entire, glabrous above; secondary veins 20–26 in each side of midrib, glabrous or puberulous below. Inflorescence terminal, involucrate head, rachis glabrous; peduncle 3–6 cm long, terete, glabrous; bracts orbicular to ovate, 10–16 × 7–25 mm, pubescent, green acute to acuminate at apex, persistent. Pedicels 0.5–1 mm long. Flowers 20–23 mm long, pubescent. Calyx 15–17 mm long, lobes 2.5–3.5 mm long, lanceolate, acute or acuminate, ciliate, pale green. Corolla funnel-form, 17–20 mm long, yellow, densely villous on both sides with a dense ring of villous hairs at the throat; lobes triangular-ovate, 4.5–5.5 × 3–3.5 mm, acute at apex, spreading, densely villous, recurved. Stamens inserted at the mouth of corolla tube; filaments 1–1.25 mm long; anthers oblong-linear, 3–3.5 × ca. 1 mm, pale yellow; style filiform, 6 mm long, glabrous, white; style branches 2, linear lanceolate, 3–4 mm long, glabrous. Fruits and seeds unknown.

Flowering:— From May to June.

Etymology:—The specific epithet refers to the yellow colour of the corolla.

Distribution, Ecology, Biotic association and Conservation status:— Leptomischus flaviflorus is known only from Namdang, Changlang district, Arunachal Pradesh, North-East India. It grows in small pockets at moist shady places along with Commelina Linnaeus (1753: 40) sp. , Pilea Lindley (1821 : tab. 4) sp., Pollia Thunberg (1781: 194) sp. and etc. It might be endemic to this area. If this is the case, its area of occupancy is estimated to be less than 5 km 2. Until now, two populations withless thanfive individuals each were observed from this area after a detailed search. Moreover, the proposed new species perceive serious threat due to deforestation, widening of the roads, and other developmental activities which may lead to loss of its natural habitat. Based on the present knowledge and available data, conservation status is assessed as Critically Endangered (CR)B1a,b(i,ii) + B2b(ii,iv,v) ( IUCN 2017).

Figures

FIGURE 1. Leptomischus flaviflorus. A. Habit. B. & C. Inflorescence (inset stipule). D. Flower with bract. E. Stipules. F.Bracts, adaxial and abaxial side. G. Calyx split-opened. H. Corolla,side view. I. Corolla split-opened. J. Corolla split-opened, showing anthers. K. Ovary with style and stigma. Photos by V.S. Hareesh.