Begonia murlenensis N.Krishna & Pradeep, 2021

Krishna, Nikhil, Pradeep, Ayilliath Kuttiyeri, Amrutha, Athalappil & Jayakrishnan, Thachat, 2021, A new species and a new record of Begonia (sect. Platycentrum, Begoniaceae) from northeastern India, Phytotaxa 482 (3), pp. 261-267 : 262-266

Begonia murlenensis N.Krishna & Pradeep sp. nov. ( Figs. 1 & 2 )

The short tuberous rhizome and anther shape of Begonia murlenensis most closely resemble B. manhaoensis but the new species can be distinguished by its smaller size, lamina being unlobed with brown bulbils and plantlets at the sinus (vs. shallowly lobed without any bulbils or plantlets at sinus), veins being sparsely scabrous abaxially (vs. pubescent-villous). The petioles with only a single groove (vs. petiole sulcate with many grooves), and the bracts being oblong-elliptic, 9–14 × 3–6 mm, and pale green (vs. ovate, 19–23 × 8–16 mm, reddish)

Type:— INDIA: Mizoram, Champhai District, Rabung , Murlen National Park , 23°40’51.4’’ N, 93°13’43.9’’ E, 25 July 2017 Nikhil Krishna 159652 (Holotype, CAL!, iso CALI!) .

Monoecious, acaulescent, rhizomatous, with a tuberous base, perennial herb, 20–28 cm tall including inflorescence. Rhizome brown, reduced, tuberous under the soil. Stipules persistent, ovate-triangular, 16–17 × 5–7 mm, pale green, base truncate, apex aristate, arista 2 mm long, margins entire, abaxially sparsely hairy with brown tomentum. Leaves: with brown bulbils and plantlets at sinus; petiole 10–18 cm long, 2.8–3.5 mm diameter, with a single groove, pale green, pale brownish red towards base, sparsely villous-glabrous; lamina asymmetric, unlobed, 10–15 × 8–11 cm, green above with white-silver spots in between the veins, and white-silver spots forming a discontinuous circle bordering the margins, pale green-pale to pinkish beneath, broadly ovate, base asymmetrically cordate, apex acute, margin subentire or weakly undulate with short hairs, adaxial surface glabrous or sparsely scabrous, abaxial surface sparsely villous at base of the veins, sparsely scabrous along the veins, 7–8-veined from base. Inflorescence axillary, bisexual, dichotomously branched at base, protandrous with male flower basal and female flower distal; peduncle 12–20 cm long, slightly grooved, reddish towards base, glabrous. Bracts caducous, oblong-elliptic, 9–14 × 3–6 mm, pale green, apex acute with a short mucra, margins entire, glabrous. Male flowers: opening earlier than female flowers: pedicel 2.5–2.8 cm long, pale pink, pale green towards apex, greenish at the base, glabrous; tepals 4, outer 2 larger, ovateelliptic, 1.7–2.2 × 1.2–1.5 cm, white-pale pink, base rounded, apex obtuse, margins entire, adaxially glabrous, abaxially sparsely strigose; inner 2 smaller, elliptic, 1.7–1.8 × 1.2–1.3 cm, white, base rounded apex obtuse to acute, recurved, margins entire, abaxially and adaxially glabrous; androecium symmetric, stamens 80–85, fused on a short column; anthers obovate-elliptic, 1.5–3 mm long, connective produced above the cells, apex obtuse-acuminate, dehiscence through longitudinal slit; filaments yellow, 1–2 mm long. Female flowers: nodding; pedicel 17–19 mm long, pale green, glabrous; outer tepals 2, elliptic-oblong, 12–13 × 9–10 mm, white-pale pink, base rounded, apex obtuse to slightly emarginate, glabrous on both surfaces; inner tepals 3, obovate-elliptic, 11–12 × 7–9 mm, white-pale pink, base truncate, apex obtuse, glabrous on both surfaces; ovary pale green, wings 3, unequal, glabrous; locules 2, placentae axile, bifid; styles 2, connate at base, bifid from about half of their length, twisted once at apex, stigmatic papillae a folded band connecting the two stylar lobes, band 3–4 times folded. Fruit: a capsule, wings unequal, green, lateral wings c. 10 × 3 mm; larger wing 15–17 × 6–8 mm, elongating away from the styles, apex rounded-muricate, dehiscent on both sides of the wings. Seeds numerous, oblong in outline, c. 0.32 × 0.23 mm light brown.

Distribution:— India. Known only from type locality, Rubung, Murlen National Park, Mizoram in northeastern India ( Fig. 4B ).

Habitat and ecology:— Begonia murlenensis occurs along the moist shady slopes near streams at an elevation between 800–900 m along with B. roxburghii (Miq.) A.DC. , Zingiber mizoramensis Ram. Kumar, Sushil K.Singh & S.Sharma , and Selaginella sp.

Flowering & fruiting:— Flowering from last week of August to October and fruiting from late October to November.

Etymology:— The specific epithet is derived from the name of the type locality, Murlen National Park in Mizoram.

Notes: Plants observed in their natural habitat as well as plants growing at Calicut University Botanical Garden consistently have white-silver spotted leaves. The discontinuous, circular, white-silver spotted outline of the lamina is also constant in the observed populations. However, further studies are required to confirm these variegation characters, as they are variable in many other begonias.

Figures

FIGURE 1. Begonia murlenensis N. Krishna & Pradeep,A. Flowering plant; B. Male flower; C. Female flower; D. Male tepals; E. Female tepals; F. Androecium; G. Stamen; H. Single style separated; I. Fruit; J. Cross section of ovary; K. Seed.

FIGURE 2. Begonia murlenensis N. Krishna & Pradeep, A. Habit & habitat; B. Cultivated individual; C. Tuberous base of the rhizome; D. Cross section of petiole; E. Bulbils and plantlets at sinus; F. Lamina; G. Male flowers; H&I. Female flowers; J. Male tepals; K. Female tepals; L. Androecium; M. Stamens; N. Styles; O. Style separated; P. Fruit; Q. Cross section of ovary; R. Seeds. (Photos: A–R by Nikhil Krishna).

FIGURE 4. Distribution map: A. Begonia zhongyangiana W.G.Wang & S.Z.Zhangin China & India; B. Begonia murlenensis.