Begonia ambanizanensis Scherber. & Duruiss., 2019

Scherberich, David & Duruisseau, Jacky, 2019, Three new species of Begonia sect. Erminea (Begoniaceae) from north-east Madagascar, Adansonia (3) 41 (7), pp. 59-67 : 60-62

Begonia ambanizanensis Scherber. & Duruiss. , sp. nov.

( Fig. 2 )

Begonia ambanizanensis Scherber. & Duruiss. , sp. nov. shares with B. antongilensis var. antongilensis the tuberous habit, with sub-caulescent stems, the symmetric, basally rounded to scarcely cordate blades, the number of perianth segments in male and female flowers and dry material have the same typical yellow brown color. It differs however substantially by the sub-orbicular shape of the leaf blade vs ovate-lanceolate in B. antongilensis and the absence of a staminal column.

TYPUS. — Madagascar. Analanjirofo region: Masoala Peninsula , Ambanizana, “S Trail” (S of Androka River ) climbing into hills SE of Ambanizana, 15°38’S, 49°59’E, 150-700 m, 1.XI.1992, Schatz et al. 3381 (holo-, MO [ MO-5567669 ]! ; iso-, P [ P06803304 ]!, TAN!, WAG [ WAG.1572957 ]!) .

PARATYPES. — Madagascar. Analanjirofo region, Maroantsetra: Mountains NE of village of Ambanizana, along trail across Masoala Peninsula toward Antalaha, 560 m, 20.X.1986, Lowry et al. 4197 ( MO [ MO-3437123 ]!, WAG [ WAG.1572932 ]!) ; Cap Masoala Grand Parc , sources d’Anaovanandrano (confins), 15°36’S, 50°00’E, 630 m, 27.IX.2003, Wohlhauser et al. 658 ( G [ G00418726 ]!, WAG [ WAG.1572931 ]!) .

DISTRIBUTION AND ECOLOGY. — Begonia ambanizanensis Scherber. & Duruiss. , sp. nov. is only known from the mountains East of the Ambanizana village ( Fig. 1 ), in dense forest, on moss covered rocks or as an occasional epiphyte on fallen logs, at an altitude of around 150- 630 m. It has been found flowering from September to November.

CONSERVATION STATUS. — Although the new species is only known from three collections within the periphery of the Masoala National Park, the two collections with GPS data are separated by a direct line of about 3.6 km. It is obvious that little has been explored of that area within the park, so that we do not know the actual extent of distribution of B. ambanizanensis Scherber. & Duruiss. , sp. nov. and if it is common or established as fractioned populations. Furthermore, satellite observations with Google Earth images from July 2014, although a few years old now, do not seem to show deforestation in that part of the park. It is estimated that there is not enough evidence to indicate that the new species might be under threat, therefore a preliminary status “LC” is proposed for now, following the IUCN Red List Categories and Criteria ( IUCN 2012).

DESCRIPTION

Tuberous perennial lithophytic herb with short clumping stems and spreading leaves.

Tuber

Small, 10-25 mm, irregular, strongly adherent.

Stem

Herbaceous, to 7.5 cm. Internodes short, to 2 cm.

Stipules

Persistent, the margins entire.

Leaves

2-8, somewhat succulent; petiole to 10 cm long, 1-3 mm diam., canaliculate, glabrous, red; blade sub-orbicular 3-11.5 cm long, 3.3-12 cm wide., sub-symmetric, base rounded to cordate, glabrous, medium green on adaxial side, conspicuously paler on abaxial side, drying brown to yellow-brown, with minute darker glands on both sides; venation basally 7-9 palmate, major veins then pinnate with 1-4 secondary veins on each side; midrib and primary lateral veins slightly raised on abaxial side.

Inflorescence

Monochasial, occasionally dichasial cyme, solitary or sometimes two, axillary, pauciflowered, bisexual, seemingly protandrous but female flower appearing early, longer than leaves, axis 6-13 cm long, 1-2 mm diam.; bracts conspicuous, enclosing buds, 6-14 mm, early deciduous; bracteole absent; perianth segments pink, sometimes paler at apex.

Male flower. Perianth segments 4, free, pedicel 10-20 mm; outer perianth segments elliptic-obovate, rounded at apex 7-9.5 × 4-5.5 mm; inner perianth segments elliptic c. 6-7 × 3.3-3.5 mm; stamens 10-12; androecium zygomorphic; filaments free 0.8-1.4 mm; anthers as long or longer than filament, oblong, 1.4-1.7 mm, dehiscent through lateral longitudinal slits; connective not extended, yellow.

Female flower. Perianth segments 6, free; pedicel 7.5-12 mm; outer perianth segments elliptic-ovate, apex obtuse, c. 6.5-10 × 4-5 mm; inner perianth segments elliptic-lanceolate c. 6.5- 10 × 3.5-4 mm; ovary 3-winged, unequal, with one wing conspicuously larger than the two others, c. 4-5 mm long vs c. 2 mm long, placentae unknown; styles 3, free, persistent in fruit; stigma reniform, in a band, yellow.

Fruit

3-winged dry capsule, nodding, the wings unequal.

Seeds

Unknown.

REMARKS

Begonia ambanizanensis Scherber. & Duruiss. , sp. nov. is atypical in section Erminea by the absence of a staminal column, a feature it shares only with B. bosseri .

Figures

FIG. 2. — Begonia ambanizanensis Scherber. & Duruiss., sp. nov.: A, habit; B, leaf, adaxial side; C, male flower, front view; D, male flower, side view; E, androecium; F, female flower, face view; G, female flower, side view; H, styles and stigmas; A-H, Schatz et al. 3381 (Drawing: Vanessa Damianthe).

FIG. 1. — Geographic distribution of Begonia ambanizanensis Scherber.& Duruiss.,sp.nov.,Begonia ambodiforahensis Scherber. & Duruiss.,sp.nov.and Begonia harimalalae Scherber. & Duruiss., sp. nov. in north-east Madagascar.