Begonia xanthina Hook.

Gyeltshen, Phub, Hughes, Mark, Zangpo, Pema, Jamtsho, Sherab, Phuntsho, Tashi, Choden, Tshering, La, Cheten & Wangchuk, Tandin, 2022, ONE NEW SPECIES AND FOUR NEW RECORDS OF BEGONIA (BEGONIACEAE) FROM BHUTAN, Edinburgh Journal of Botany 79 (1922), pp. 1-18 : 14-17

Begonia xanthina Hook. [§ Platycentrum ], Bot. Mag. 78: t. 4683 (1852); Clarke in Hooker,

Fl. Brit. India 2: 644 (1879); Clarke, Bot. J. Linn. Soc. 18: 119 (1881); Grierson, Fl. Bhutan 2: 245 (1991); Gu, Peng & Turland in Wu, Raven & Hong, Fl. China 13: 204 (2007); Uddin, J. Econ. Taxon. Bot. 31: 595 (2007); Dash, Bull. Arunachal Forest Res. 26: 41 (2010); Camfield & HUghes, EUr. J. Taxon. 396: 102 (2018).

Platycentrum xanthinum (Hook.) Klotzsch, Abh. Königl. Akad. Wiss. Berlin 1854: 243 (1855). – Type: Cultivated collection, 1852, Nuttall s.n. (lectotype K [ K000739937 ], designated by Camfield & HUghes, 2018). Cultivated at Rainhill , near Preston , from vegetative material collected in the wild from ‘ Bootan’ (West Bengal, India) in 1850 by Booth.

Begonia xanthina var. pictifolia Hook., Bot. Mag. 85: t. 5102 (1859). – Type: Hooker, Bot. Mag. 85: t. 5102 (illustration) (1859).

Begonia lazuli Linden ex K.Koch, Wochenschr. Gärtnerei Pflanzenk. 1: 339 (1858). Begonia xanthina var. lazuli Hook., Bot. Mag. 85: t. 5107 (1859). – Type: Hooker, Bot. Mag. 85:

t. 5107 (illustration) (1859).

Begonia poecila K.Koch, C.Koch & Fint., Wochenschr. Gärtnerei Pflanzenk. 1: 338 (1858). – Type: Unknown. Figure 9.

Monoecious, rhizomatous herb up to 50 cm tall. Rhizome elongate creeping, 2–10 cm

long, pilose, reddish brown. Stipules triangular-ovate, 10–20 × 15–18 mm, apex acute, margin entire, revolute, abaxially puberulent, sometimes pilose on midrib, pale whitish pink, caducous. Leaves: lamina basifixed, asymmetrical, ovate to broadly ovate, 4–25

× 5–23.5 cm, apex acute to shortly acuminate, base oblique cordate with lobes not overlapping, margin toothed at the end of the veins with smaller teeth between, with sparse hairs, adaxial surface dark green with silver-green variegation between the main veins, glabrous, abaxial surface purplish green, purple veins and nerves, red villose on veins; venation palmate, veins 6–10; midrib prominent underneath; petiole up to 22 cm long, light red, pale white linear dots, glabrous to sparsely puberulous. Inflorescence protandroUs, cymose, terminal or axillary, Up to 40 cm long, staminate flowers distal and pistillate flowers basal; pedUncle terete, 8–25 cm long, reddish, glabrous or white tomentose. Bracts ovate-lanceolate, 15–25 × 8–10 mm. Staminate flower: pedicel light red, up to 26 mm long, glabrous; tepals 4, yellow to yellowish red; outer tepals ovate, 16–20

× 16–17 mm, apex rounded to obtuse, margin entire, outer surface sparsely villous at base, inner surface glabrous; inner tepals elliptic to elliptic-obovate, 16–19 × 9–12 mm, apex rounded to obtuse, margin entire or crenate, both surfaces glabrous; androecium symmetrical, Up to 10 mm long; stamens c.60, yellow, filaments 1–3.5 mm long, unequal, fused at base; anther fusiform to oblong-obovate, 2.5–4.5 mm long, connective extended, apex acuminate, dehiscing through lateral slits. Pistillate flower: pedicel reddish, 1–2.5 cm long, light red, glabrous; ovary ellipsoid, reddish at anthesis, unequally 3-winged, glabrous, 2-locular; placentation axillary, 2 branches per locule; styles 2, yellow, connate near the base into a short stalk, up to 5 mm long; stigmas strongly spiralled, twisted twice, persistent; tepals 5, unequal, yellow to yellowish red, apex obtuse or retuse, glabrous;

outer tepals larger than inner tepals, obovate or elliptic-obovate, 15–20 × 8– 1.2 mm, margin entire or undulate; inner tepals obovate, 13–17 × 6–11 mm, apex obtuse to retuse or crenate. Capsule reddish, nodding, glabrous, unequally 3-winged; dorsal wing oblong, 18–23 × 11–18 mm, apex obtuse or rounded; lateral wings much narrower, 12–15 × 4–6 mm.

Phenology. Flowering from June to September, fruiting from June to October.

Distribution and habitat. China, India, Nepal, and new to Bhutan (Sarpang). The species prefers rocky substrates in subtropical and warm broadleaved forests at 600–1800 m elevation. See Figure 5.

Specimens examined. BHUTAN. Sarpang: Noonpani , 880 m, xi 2020, P. Gyeltshen 55 ( THIM18825 ) .

INDIA. Arunachal-Pradesh: Bhalukpung , vii 1970, Yandell 116 ( K) ; Mishmi Hills, 1862–1863, Griffith 2591 ( K) ; Meghalaya, Khasi Hills , xi 1886, Mann s. n. ( K) .

The two records of this species in BhUtan by Camfield & HUghes (2018) are in error. The type was collected by Booth in 1850 from in the wild, from ‘Bootan’, which was recorded in Camfield & HUghes (2018) as Bhutan. However, as ‘Bootan’ includes parts of India in Booth’s notes, it is difficUlt to conclUde with certainty that the collection is made from BhUtan. The record from Pakke Tiger Reserve of Bhutan is erroneous because the reserve is in Arunachal Pradesh, India, not inside BhUtan. Camfield & HUghes (2018) assigned the conservation category as Least Concern ( LC) due to the large distribution of the species and the amount of suitable habitat in Eastern Himalaya and China. The population found in Bhutan is stable and has a safe habitat for growth and reproduction.