Begonia griffithiana

Camfield, Rebecca & Hughes, Mark, 2018, A revision and one new species of Begonia L. (Begoniaceae, Cucurbitales) in Northeast India, European Journal of Taxonomy 396, pp. 1-116 : 39-41

Begonia griffithiana (A.DC.) Warb. [sect. Monopteron]

Figs 25 , 26A

Naturlichen Pflanzenfamilien 3 (abt. 6a): 142 ( Warburg 1894). – Mezierea griffithiana A.DC., Annales des Sciences Naturelles; Botanique, Sér. 4, 11: 144 (de Candolle 1859). – Type: Bhutan, Griffith 2504 (lecto-: K000761416, here designated; isolecto-: BM001122242).

Begonia episcopalis C.B.Clarke, The Flora of British India 2: 644 ( Clarke 1879), nom. illegit. superfl.

Citations in other publications

As B. griffithiana: Grierson (1991: 244) , Morris & McMillan (2006: 174), Uddin (2007: 594), Hughes (2008: 46), Dash (2010: 33), Morris (2011d: 142); as Mezierea griffithiana: Clarke (1879: 644) ; as B. episcopalis: Clarke (1881: 119) .

Other material

INDIA: Arunachal-Pradesh: Lohit Valley, Dening, 3 Feb. 1950, Ward 19120 ( BM, E); Pango to Mariyang, Rao 17711 (ASSAM n.v.); Sangram to Panyu River, Dash 32547 ( ARUN n.v.); Sarli to Milli, Dash 32547 ( ARUN n.v.); Tamen, Pal 78498 ( ARUN n.v.). Meghalaya: Khasia, Hooker & Thomson 2 ( K); Shillong, 24 Oct. 1872, Clarke 19046A ( K); ibid., Clarke 19046D ( BM).

Description

Caulescent, erect/cascading, monoecious herb, 50–100 cm high. Stem: slightly woody, stout at the base, more slender distally, 5–10 mm wide, puberulous, internodes 3–9 cm long. Stipules: lanceolate, 4–13 × 1–2 mm, puberulous on reverse, persistent. Leaves: petiole 0.2–1(– 5) cm long, tomentose; lamina oblong-lanceolate to lanceolate, basifixed, base shallowly cordate, 5–18 × 2–5 cm, strongly asymmetric, upper surface green, sparsely pilose to glabrous, underside green, pilose on the veins only, venation pinnate to pinnate-palmate, midrib 4–16 cm long; margin serrulate or with small teeth at ends of the main veins only, with very sparse short hairs; apex acuminate. Inflorescence: cymose, axillary to terminal, numerous; peduncle glabrous, branching 2–3 times, primary 3–5 cm, secondary 2–4 cm, tertiary 1–1.5 cm, with 2– 4 female and 4– 8 male flowers; bracts lanceolate 2–3 × 1 mm, glabrous, caduceus. Male flower: pedicel 6–10 mm long, puberulous to glabrous; tepals 4; outer tepals orbicular to oblong, 4–14 × 2–11 mm, pale pink to white, glabrous, margin entire; inner tepals lanceolate to linear, 3–9 × 1–4 mm, pale pink, glabrous; androecium with 20–30 stamens, symmetric; filaments 1–2 mm long, unequal, fused at base into a column; anther elliptic-globose, 1 mm long, dehiscing through short slits near the tip, connective slightly extended. Female flower: pedicel 10–15 mm long, puberulous to glabrous; bracteoles absent; tepals 5–6, equal, 3–4 larger and 1–2 smaller, oblong elliptic to obovateorbicular, outer tepals 6–11 × 5–7 mm, pale pink to white, glabrous, margin entire, inner tepals similar but smaller; ovary capsule oblong-ellipsoid, 5–7 × 2–3 mm, pink, glabrous, with one long triangular wing; styles 2, convoluted with slightly twisted ends, deciduous. Fruit: pendulous; capsule oblong-ellipsoid, 14–18 × 4–6 mm, red, glabrous; wing extending along the pedicel slightly, unequal, rounded triangle, 12–18 × 14 –18 mm.

Distribution and phenology

Arunachal-Pradesh to Meghalaya; also in Bhutan and Myanmar; 750–1400 m. Flowering: October to December; fruiting: December.

Conservation status Least Concern. Although B. griffithiana has a small AOO of 28 km 2 it has an EOO of 64,570 km 2 and is

found primarily in the mountains of Arunachal-Pradesh that are fairly undisturbed with plenty of suitable habitat. The species has also been found near the Dibang Wildlife Sanctuary of Arunachal-Pradesh.

Remarks

The flowers can be either pink or white ( Morris & McMillan 2006, Morris 2011d), and the fruits vary from green to pink to bright red. In the wild B. griffithiana prefers to grow on cliff faces, allowing the many branched peduncles to cascade down the cliff ( Morris 2011d). This species is vegetatively most similar to B. nepalensis which has only 2 tepals on the male flowers and has leaves which are adaxially glabrous. The leaves of B. nepalensis can get much longer and broader than those of B. griffithiana which are always linear in shape. The wing on the fruit is larger and broader on B. nepalensis (see Fig. 26 ) and the female flowers are about 1 cm wider.

Figures

Fig. 25. Map showing the location of B. griffithiana (A.DC.) Warb. specimens.

Fig. 26. Difference in fruit shape. A. B. griffithiana (A.DC.) Warb. B. B. nepalensis (A.DC.) Warb. Drawn by Rebecca Camfield. A from Griffith 203 (K) and 2504 (K); B from Stainton 8906 (E) and Cave s.n. (E00013877).