Begonia henrilaportei Scherber. & J. Duruisseau

David Scherberich & Jacky Duruisseau, 2016, Begonia henrilaportei Scherber. & J. Duruisseau (Begoniaceae), a new endemic species from the Masoala peninsula, Madagascar, Candollea 71 (1), pp. 13-18 : 14-17

Begonia henrilaportei Scherber. & J. Duruisseau , spec. nova

( Fig. 2 , 3 ).

Typus: Madagascar. Prov. Toamasina: Masoala Peninsula, Ambanizana , trail along coast 3-6 km S of Ambanizana , 15°39’S 49°58’E, 30.X.1992, fl., Schatz et al. 3370 (holo-: P [ P00137297 ]!; iso-: MO-2740146 !, TAN!, WAG!).

Begonia henrilaportei Scherber. U J. Duruisseau differs from all other Malagasy species by the unique combination of creeping stem, linear-lanceolate blades with pinnate venation, male flowers composed of 2 perianth segments and female flowers with 4 segments.

Perennial lithophytic herb; Stems creeping, to 30 cm long and 3 mm wide, turning woody at the base, branched, pale green to red, sparsely hairy; internodes 0.5-2.5 cm long. Stipules persistent, narrowly triangular, the margins entire, 0.5-0.9 cm long, pale green to red. Leaves numerous, alternate, straight, simple, to 5-14 cm long; petiole short, 0.5-2.5 cm, green tinted red, sparsely hairy. Blade symmetric to slightly asymmetric, linear-lanceolate, 5-11 X 0.4-1.3 cm, attenuate at the base, the margins strongly incised, 6-10 incisions per side; adaxial surface pale green, glossy, with white granular inclusions; abaxial surface paler, semi-glossy, margins tinted red; midrib raised on adaxial side, convex, darker green, sometimes with a few trichomes on upper part, convex and tainted red on abaxial side; venation pinnate, with 6-10 veins per side, darker. Inflorescence axillary, monochasial, pauciflowered, bearing 2-5 flowers at summit, generally bisexual, protandrous, the male flowers basal, bearing a solitary female flower distally; peduncle to 1.5-7.5 cm, pale green, sometimes tinted pink in upper part, bracts early caducous; bracteoles absent; perianth bright pink, the segments rounded at apex. Staminate flowers perianth composed of 2 segments, free, suborbicular, 5-7.5 mm X 5-7 mm; Androecium zygomorphic; stamens 8-11, fasciculate, free, filaments 1.5-2 mm, white; anthers 1.3-1.6 mm oblong, emarginate at apex, pale yellow, about nearly as long as filaments, dehiscent with lateral longitudinal slits. Pistillate flowers with perianth composed of (3-) 4 segments, free; ovary 3-winged, with one wing conspicuously larger than the two others, pale green, composed of 3 locules, placentation axillary; placental branches 2 per locule; styles 3, free, bifid, white to pale pink, persistent; stigma reniform. Fruit a 3-winged dry capsule, nodding, the wings unequal, main wing about 7 mm long and 10 mm wide, the lateral ones about 2.5 mm long and 8.5 mm wide. Seeds globose-ovoid, about 0.3 mm, tegument reticulate.

Etymology. – This new species is dedicated to Henri Laporte, explorer, keen Begonia grower and collector, who discovered and introduced into cultivation many species from Madagascar. Henri died of severe malaria in December 2001, which he contracted on a trip to Madagascar.

Phenology. – Flowering has been observed from November to March.

Distribution and ecology. – Known only from the type locality, along the path connecting Ambanizana to Ambodiforaha near the sea shore, on the west coast of the Masoala peninsula, in the Analanjirofo region, Madagascar ( Fig. 1 ). Begonia henrilaportei is a lithophytic hygrophilous species, on granitic rocks (gneiss) in streams, growing among mosses, pteridophytes and Melastomataceae , close to the sea.

Conservation status. – The only known location of B. henrilaportei lies in the periphery of the Masoala National Park, along a path that is used everyday by farmers and inhabitants of nearby villages. About 10-20 individuals only have been observed and despite a thorough exploration of the surrounding areas on multiple expeditions, no other population has been found so far. We therefore assigned a preliminary conservation status of “Critically Endangered” [CR C2a(i)] ( IUCN, 2012).

Notes. – The only other species from section Nerviplacentaria A. DC. with a long, creeping stem is B. lyallii but that species differs by the ovate-triangular to ovate-elliptic blades with palmate venation. It is also super cially similar to and has been mistaken in herbarium with B. nana and B. bogneri but these species both belong to sect. Erminea A. DC. and differ by the tuberous and acaulescent habit, male flowers composed of 4 perianth segments and female flowers with 5-6 segments.

The type, Schatz et al. 3370, was determined in P [P00137297] as B. nana by G. Aymonin ( Fig. 3 ) and in MO and WAG as B. bogneri by J.J.F. de Wilde. A comparative table with distinguishing features between the new species and the morphologically closely related species is presented in Table 1 .

Paratypi. – Madagascar. Prov. Toamasina: Maroantsetra, Ambanizana , along path between Ambanizana-Andranobe, 15°39’19”S 49°57’39”E, 11 m, 25.X.2004, fl., Antilahimena 2970 ( MO-6340835 , P [ P05619948 ], WAG) ; Andranobe, N to Ambanizana , 15°41’S 49°58’E, 5-10 m, 26.II.1999, fl., McPherson 17693 ( MO, TAN) ; S. of Ambanizana , 15°39’S 49°57’E, 15 m, 16.XI.1993, fl., van Nek 2087 ( TAN, WAG [ WAG0232448 , WAG0232449 ]) ; 4 km au S du village d’Ambanizana , rochers sur le sentier qui relie Ambanizana à Ambodiforaha en longeant la mer, 21.III.2013, fl., Scherberich 969 ( LYJB [ LYJB0 10461 , LYJB010462 ]) [Plante cultivée au Jardin Botanique de Lyon sous le numéro 0 60667, collectée à l’origine par H. Laporte].

Figures

Fig. 1 – Distribution of Begonia henrilaportei Scherber. & J. DUrUisseaU (white stars) in the Masoala Peninsula, Madagascar plotted on a map of forest cover in 2000 (grey) following Harper et al. (2007).

Fig. 2. – Begonia henrilaportei Scherber. & J. Duruisseau. A. Habit in the type locality; B. Leaf adaxial surface; C. Apex of stem; D. Leaf abaxial surface; E. Inflorescence showing female flower and male flower bud; F. Stamens. [Photos: A: J. Duruisseau; B-F: D. Scherberich]

Fig. 3. – Holotype of Begonia henrilaportei Scherber. & J. DUrUisseaU. [Schatz et al. 3370, P] [© Muséum national d’Histoire naturelle, Paris. Reproduced with permission]

Tables

Table 1. – Morphological and ecological features distinguishing Begonia henrilaportei Scherber. & J. Duruisseau from B. bogneri Ziesenh., B. lyallii A. DC. and B. nana L’Hér.

Characters	B. bogneri	B. henrilaportei	B. lyallii	B. nana
Section	Erminea A. DC.	Nerviplacentaria A. DC.	Nerviplacentaria A. DC.	Erminea A. DC.
Tuber presence	yes	no	no	yes
Blade shape	filiform	linear-lanceolate	ovate-triangular to ovate-elliptic	ovate-lanceolate
Blade base	attenuate	attenuate	cordate	attenuate to cordate
Venation	secondary venation absent	pinnate	palmate	pinnate
Blade margins	dentate	incised	entire to finely dentate	dentate
Pubescence	glabrous	glabrous to weakly hairy	glabrous to glabrescent	glabrous
Inflorescence	axillary, cymose	axillary, cymose	axillary, cymose	axillary, cymose
Bract	caducous	caducous	caducous	unknown
Number of tepals in male flower	4	2	2	4
Stamens	12	8-11	12-32	9-12
Number of tepals in female flower	6	(3-)4	4	5-6
Fruit	alate, membranous, dehiscent	alate, membranous, dehiscent	alate, membranous,	alate, membranous, dehiscent
Ecology	on granite, 50 m	humid rocks (gneiss)	dehiscent humid places in shady forest, on gneiss, 400-1000 m	humid rocks (gneiss or quartzites) in shady forest, 50-300 m