Begonia cathcartii Hook.

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 : 30-33

Begonia cathcartii Hook. f. [sect. Platycentrum]

Figs 19–20

Illustrations of Himalayan Plants: 13 ( Hooker 1855). – Platycentrum cathcartii (Hook.f.) Klotzsch, Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin: 245 ( Klotzsch 1855 [‘1854’]).

– Type: India, Sikkim, Darjeeling, Hooker s.n. (lecto-: K000373057 , here designated ; isolecto-: K000373056 ).

Begonia nemophila Kurz , Journal of the Asiatic Society of Bengal 46 (2): 108 ( Kurz 1877).

– Type: Myanmar, East of Tounghoo, Martaban Hills , Kurz s.n. (n.v.) .

Citations in other publications

As B. cathcartii: Klotzsch (1855 [‘1854’]: 245), de Candolle (1864: 349), Clarke (1879: 646), Clarke (1881: 119), Craib (1931: 772), Hara (1971: 84), Hara et al. (1979: 181), Grierson (1991: 244), Chauhan (1996: 175), Kress et al. (2003: 171), Uddin (2007: 593), Hughes (2008: 24), Dash (2010: 32); as Platycentrum cathcartii: Klotzsch (1855 [‘1854’]: 125); as B. nemophila: Clarke (1879: 646) .

Other material examined

INDIA: Arunachal-Pradesh: Delei Valley, 16 Jul. 1928, Ward 8459 ( K).

Description

Rhizomatous, erect, monoecious herb, 30–60 cm high. Rhizome: ca 10 mm wide, densely strigose. Stem: stout, ca 5 mm wide, red reflexed strigose, internodes up to 23 cm long, much shorter at the rhizomatous base of the plant. Stipules: ovate, 9–10 × 3–4 mm, glabrous, semi-persistent. Leaves: petiole (3–)6–13(–20) cm long, red strigose; lamina ovate to broadly ovate, basifixed, base cordate with lobes not overlapping, 15–21 × 9–15 cm, asymmetric, upper surface green, sparsely red strigose all over, underside green, sparsely red strigose mostly on the veins, venation palmate, midrib 10–15 cm long; margin minutely serrate, with hairs; apex acuminate. Inflorescence: sometimes subtended with a pair of leaves; cymose, axillary, few; peduncles sparsely red strigose, branching 2–3 times, primary 4–8 cm long, secondary and tertiary peduncles ca 1 cm long, with 1– 3 female flowers and 1– 3 male flowers; bracts lanceolate, 7–11 × 2–4 mm, fimbriate. Male flower: pedicel 18–20 mm long, pilose; tepals 4; outer tepals ovate, 15 –24 × 10–20 mm, white, red pilose on reverse near the base; inner tepals lanceolateovate, 10–15 × 8–12 mm, white, glabrous; androecium with 60–80 stamens, symmetric; filaments ca 2 mm, anther oblong elliptic, 2 mm long, not hooded, connective extended. Female flower: pedicel 16–21 mm long, pilose; bracteoles absent; tepals 5, equal, ovate, outer tepals 20–25 × 12–15 mm, white, red pilose on reverse near base, inner tepals similar but smaller; ovary 2-locular, placentae bifid, capsule ellipsoid, densely red strigose, with one long oblong wing and two short triangular wings; styles 3, deeply forked once and twisted once. Fruit: recurved, 29–42 × 12 –16 mm; capsule ellipsoid, 18–20 × 7–9 mm, sparsely red strigose; wings extending along the pedicel slightly, subequal; longest rounded oblong, 15–24 × 11–15 mm; shortest triangular, 7–9 × 12–16 mm.

Distribution and phenology

Arunachal-Pradesh; also in Nepal, Sikkim, Bhutan, Myanmar and Thailand; 1800–2100 m. Flowering: April to June; fruiting: May to July.

Conservation status

Least Concern ( Hughes 2008). Begonia cathcartii is a widespread species with no significant change in distribution in recent years to warrant a change in its status. This species is known to occur in Doi Inthanon National Park in Thailand.

Remarks

Known in the study area from one specimen that lacked female flowers; the description was augmented using the protologue and specimens from the Eastern Himalayas. Begonia cathcartii is characterized by red reflexed hairs more or less all over the plant; B. thomsonii , also in B. sect. Platycentrum , shares having red hairs, but is a much smaller plant and the indumentum is denser and finer.

Figures

Fig. 19. Map showing the location of B. cathcartii Hook.f. specimens.

Fig. 20. Illustration of B. cathcartii Hook.f. by W.H. Fitch (Hooker 1855). 1–3. Stamen, front, back and side view. 4. Pollen. 5. Immature fruit. 6. Cross-section of fruit showing ovary placentation. Image from the Biodiversity Heritage Library, digitized by the Peter H. Raven Library.