Begonia masoalaensis M.Hughes, 2011

Hughes, Mark, 2011, A new species of fleshy-fruited Begonia (Begoniaceae) from the Masoala Peninsula, Madagascar, Adansonia (3) 33 (1), pp. 81-85 : 82-84

Begonia masoalaensis M.Hughes , sp. nov.

( Fig. 1 )

Begonia masoalaensis sp. nov. tuberis praesentia et foliis maculatis marginibus sinuosis a ceteris speciebus madagascariensibus et insulis affinibus cum fructu carnoso ( B. comorensis , B. humbertii , B. oxyloba et B. salaziensis ) differt.

TYPUS. — Madagascar. Antsiranana, Masoala Peninsula, forest surrounding research station at Anronabe on west coast, 15°39’30”S, 49°57’30”E, 0-600 m, 19.II.1992, Zjhra & Hutcheon 175 (holo-, MO; iso-, E).

DESCRIPTION

Tuberous repent herb to 10-20 cm high. Tuber c. 2 × 0.8 cm when dry, elliptic, narrowing at the ends, circular in cross section. Stem to c. 8 cm long, with many adventitious roots, hairy, more so towards the apex, hairs simple, c. 1.5 mm long. Stipules persistent, c. 6 mm long with hairs on the keel. Leaves 2-3 in number; petiole 1-5 cm long, densely covered in 1.5 mm long simple hairs; lamina green with an even covering of tiny white or red dots, 8-22 × 5-11 cm in total, 7-16 cm long from point of petiole attachment to tip, ovate, markedly asymmetric, cordate at base, venation palmatepinnate; margin sinuate, denticulate with a fringe of hairs c. 0.25 mm long. Inflorescence terminal, spicate, bisexual, usually with two main axes, each terminating in a female flower, primary peduncle c. 3 cm long; bracts persistent, 2-3 mm long, glabrous; male flowers with 4 white tepals, outer sub orbicular, c. 5 mm in diameter, inner linearelliptic to c. 5 mm long; stamens c. 15, filaments 1.5 mm long, free, anthers just over 1 mm long, elliptic-oblong, not hooded, dehiscing through slits running the entire length of the anther; female flowers with 4 white tepals, similar in shape and dimensions to those in the male flowers, ovary cigar-shaped, c. 1 cm long on flowering, stigmas 3, stigmatic surface in a simple U-shaped band. Fruit fleshy, cigar-shaped, c. 3 cm long, 3 mm wide when dried, glabrous, indehiscent; placentation axile, placentae bifid. Seeds barrel-shaped, size at maturity not known, collar cells less than ⅓ the length of the seed.

DIAGNOSTIC CHARACTERS

Begonia masoalaensis differs from other Malagasy and neighbouring islands species with fleshy fruit ( B. comorensis , B. humbertii , B. oxyloba and B. salaziensis ) in having a tuber and spotted leaves with sinuate edges.

CONSERVATION ASSESSMENT

The Masoala National park is currently well protected ( C. Kremen pers. com.). However, this species is currently known only from the type locality, which is at a low altitude just within the border of the reserve, and hence is considered to be Vulner- able ( VUD2 ) ( Standards and Petitions Working Group 2006) .

Figures

FIG. 1. — A, Begonia masoalaensis M. Hughes, sp. nov., bearing two female flowers with the scars of the shed male portion of the inflorescence below: B, cross section of ovary; C, male flower. Scale bars: A, C, 1 cm; B, 5 mm.