Begonia naga Nikhil & Pradeep, 2018

Krishna, Nikhil, Pradeep, Ayilliath Kuttiyeri & Jayakrishnan, Thachat, 2018, Begonia naga (Begoniaceae, sect. Platycentrum), a new species from Nagaland, India, Phytotaxa 381 (1), pp. 6-11 : 7-10

Begonia naga Nikhil & Pradeep , sp. nov. (sect. Platycentrum ) ( Figs. 2 & 3 )

Begonia naga resembles B. beddomei Hook. f. but differs by having 2 stylar branches (not 3), leaves being caulescent at the flowering period (not arising from the rhizome), anther connective narrow and acuminate (not broad and subacute), female tepals being 5 (not 8) with a pale brownish band on the outer tepals. Diagnostic characters are summarised in Table 1.

Type:— INDIA. Nagaland, Mokokchung district, Mokokchung , 800–1100 m, 29 July 2016, Nikhil Krishna 148568 (Holotype CAL!; Isotypes MH!, CALI!) .

Monoecious, rhizomatous, perennial herb, 30–40 cm tall including inflorescence. Acaulescent in the vegetative stage, caulescent with a short stem during flowering. Stem 4–8 cm long dark purplish with white streaks. Stipule pale green– pale brown, triangular, 2–2.1 × 0.5–0.6 cm, base truncate, apex acute, mid nerve extending as a mucro, mucro 3–4 mm long, margin entire, caducous. Leaves simple, alternate; petiole pale green, reddish towards base, 12–45 cm long, grooved above with narrow lateral wings, young partsdensely lanate; lamina green above and beneath, broadly ovate, 20–24 × 12–17 cm, base asymmetrically cordate, apex acuminate, margin shallowly lobed, lobes ovate–triangular, margin coarsely strigose or glabrous, upper surface occasionally pilose, especially on nerves towards the base, often slightly tomentose, lower surface densely lanate on the veins as in petiole, 5–7 nerved from base. Inflorescences axillary, bisexual, dichotomously branched, protandrous with male flower basal and female flower distal; peduncle 10–30 cm long, green, reddish at base with white longitudinal streaks, glabrous. Bracts reddish, ovate, 1.9–2.2 × 0.8– 1.5 cm, caducous, base truncate, apex acuminate, margins entire, slightly wavy, glabrous. Male flower pedicel white, 2.2–2.7 cm long, greenish at the base, strigose; tepals 4; outer tepals 2, elliptic, 2.2–2.4 × 1.4–1.6 cm, white–pale pink, base rounded, apex obtuse, margin entire, reflexed, abaxial side strigose; inner tepals 2, oblong, 1.7–1.9 × 0.8–1 cm, white, base cuneate, apexacute, recurved, glabrous on both surfaces; androecium symmetric, stamens monadelphous, ca. 100; anthers narrowly oblong, 2–3 mm long, connective produced above the cells, narrow, acuminate, dehiscence through longitudinal slits; filaments 2–2.5 mm long. Female flower nodding; pedicel 1.7–1.9 cm long, pale green, pinkish towards peduncle, strigose; outer tepals 2, elliptic–oblong, 2–2.2 × 1.1–1.3 cm, pale pink, white towards margin, base truncate, apex obtuse, glabrous on both surfaces; inner tepal 3, oblong–obovate, 2–2.1 × 0.9–1 cm, pale pink, base obtuse–cuneate, apex acute with a reflexed triangular lobe, glabrous on both surfaces; style 2, connate at base, stigmatic band 7 times folded; ovary pale green, wings 3, unequal, lateral wings sparsely strigose at apex; locules 2, placenta bifid, ovules arranged on an axile placenta. Capsule green, wings unequal, lateral wings ca. 1.5 × 0.6 cm, middle wing 1.7 × 2.1 cm, dehiscent on both sides of the two lateral wings.

Etymology:— The specific epithet ‘Naga’ is derived from the name of the inhabitants of the state of Nagaland, India.

Distribution, habitat and ecology:— It is distributed in the forest margins of Mokokchung and Pherima Village of Nagaland in Northeast India ( Fig. 1). It usually grows in moist shady areas, along with Peperomia pellucida (L.) Kunth, Phyllanthus urinaria L. and Bidens biternata (Lour.) Merr. & Sheriff at an elevation between 800–1100 m.

Phenology:— Flowering and fruiting from July to December in the field, extending up to March in green house conditions.

Additional specimen examined:— INDIA. Nagaland, Dimapur District, Pherima, 26 July 2016, Nikhil Krishna 148557 (CALI!).

Notes:— Begonia beddomei is unusual in sect. Platycentrum in having three styles and having a very broad anther connective, which is obtuse or subacute at apex. It also has white spots on the upper leaf surface, which differs from the uniform green of B. naga . However leaf spots can vary within Begonia species and we do not consider this a good diagnostic character.

Figures

FIGURE 2. Begonia naga.A. Habit; B. Showing caulescent nature during flowering; C. Inflorescence with female flowers; D. Male flower; E. Female flower; F. Tepals; G. Tepals; H. Androecium; I. Stamens; J. Style; K. Stylar branch separated; L. Cross section of ovary; M. Scanning electron microscope (SEM) image of Seed.

FIGURE 3. Begonia naga. A. Habit; B. Lamina adaxial surface; C. Male flower; D. Androecium; E. Single stamen; F. Female flower; G. Spirally twisted stylar branch; H. Fruit; I. Cross section of ovary; J. Seed.