Species
B. madecassa
Photos
5 photos
Identity
- Genus
- Begonia
- Name
- B. madecassa
- Author
- M. Keraudren, Fl. Madagascar
- Publication Date
- 1983
- Habitat
- endemic. Center (north): Amber Mountain, Bosser 20333; Diego-Suarez, Amber Mountain, Arnoult, Jard. Bot. Tan. 57; Mangindrano (upper Maevarano) to the summit of Ambohimirahavavy (Mahavavy-Androranga watershed), Humbert & Capuron 24883; High Aodroranga, Perrier of Bathie 6673; Mount Anjanaharibe, Humbert & Capuron Jard. Bot. Tan. 19; Anesika, Bealanana, Res. nat. IV, Tsilizy, RN 7140; Res. nat. IV, Bealanana, Habitat: wet rock in the rainforest, mostly on gneiss laterites, between 800 and 1600 m alt .; sometimes epiphyte; fl. Jan-Jun.
- Country
- Madagascar
- Region
- Africa
- Section
- Nerviplacentaria
- Plant Type
- Shrub-like
- Reference
- Fl. Madagascar 144:83, pl. 26. 1983.; JGSL9/08
- Article References
- Flore de Madagascar et des Comores; M. Keraudren-Aymonin & Aymonin G. 1983. — Begoniaceae. Muséum national d'Histoire naturelle, Paris, 123 p. vol. 144-145).
Plant
- Description
- Planta suffrutescens, sarmentosa, caulibus paulo divisis, sublignosis vel valde crassis, usque ad 2 m altis, 6-10 mm in diametro, juvenilibus tenuiter rubrotomentosis, demum glabrescentibus. Folia petiolo rubro glabro, 2-5 cm longo, limbo disymetrico, 9-22 cm longo, 6-12 cm lato, oblique ovato, basi cordato, tenuiter apice acuminato, glabro, marginibus integris vel vix breve dentatis. Stipulis membranaceis, lanceolato-acuminatis. lnflorescentiae mixtae, axillares, in cymas bipares instructae, multiramosae, pedunculo valde crasso, 6-18 mm longo. Florum MALE tepala 4, alborosea, exteriora majora usque ad 25 X 15 mm, interiora angustiora 3-6 mm lata. Stamina 30-35 libera, filamentis ad basim connatis, altius liberis (secus 1 mm longitudinem). Florum FEMALE tepala 5, subaequalia vel 3 majora, 2 minora, oblongua, basi constricta, 10-25 X 3-7 mm. Styli 3, profunde bifidi, segmentibus, bi-trifurcatis, apice papillosis, involutis. Ovarium oblongum, trialatum. Capsula trialata, tenuiter pedicellata, 15 mm longa, 7 mm lata, pedicello 2-3 mm longo, alis tenuibus circumdantibus capsulam. Sub-shrub with weakly branched, sub-woody or slightly crassulescent stems up to 2 m in height and 6-10 mm in diameter; young parts covered with a thin red tomentum, becoming glabrous later. Leaves with membranous stipules, lanceolate, acuminate at the apex, 18-26 x 5-7 mm, easily deciduous; petiole 5-10 cm long, glabrous; asymmetric limb, obliquely oval, pointed at tip, obliquely rope at base, 9-22 x 6-12 cm, dark green velvety above, green lighter or tinge of red below, glabrous on both sides, margins entire or very feebly and shortly dente; 5 ribs at the base, finely projecting on both sides; rib oblique secondary, tertiary veins mostly marked near margins. Inflorescences in bipillar axillary cymes, very ramified, bisexual, with rather robust peduncle, 6-18 cm long; first branches 1.5-3 cm; pink, ovate-elliptic bracts, 18-22 x 5-6 mm; pedicel thin, glabrous, 8-25 mm long. White or pink white flowers, which can be large or small. MALE flowers have 4 tepals (rarely only 2), the outer ones are larger, obovate or rbicular (in small flowers), 7-25 X 6-15 mm, the internals shorter and shorter, not more than 6 mm wide and in small flowers hardly 3 mm. Stamens 30-35 approx., Free, fasciculate, with threads very slightly welded at their base, free part 1 mm long; oblong antheres, 3 mm long. FEMALE flowers have (4-) 5 sub-equal tepals or 2 smaller than the other 3, oblong, retracted at the base, 10-25 x 3-7 mm. Ovary ovary, triaile; styles divided in 2 up to half their length, each branch very often bi- or trifid; stigmatifere floppy blade, wound at the end. Capsule with a fine pedicel, 2-3 cm long, oblong, 15 X 7 mm; 3 very rounded fine wings completely surrounding the capsule, the widest of 15 mm, the 2 small ones not exceeding 5 mm; median ribs finely marked; reticulum of the wings clearly visible, with rather dense nerves. Seeds brown, ovoid-oblong or fairly globose, 0.3-0.4 x 0.2-0.3 mm (sometimes up to 0.6 x 0.5 mm), with long rectangular meshes often well defined on one of the side. - Pl. 26, p. 85. This species may present, even on the same foot, large floral dimorphisms (flowers from 10 to more than 30 mm, sometimes 35 mm in diameter). This taxon has been taken up here as named by Humbert in a handwritten note without description, quoting simply "madecasssa H.H. (ad interim) Humbert 24883, 22493, Decar. 1909 ". In fact, Humbert 22493 specimens, with non-winged berry fruits, are to be considered as belonging to B. humbertii Keraudren. We have compared the other two batches with a number of specimens, but it should be noted that some show variations in the number of tepals (4, but sometimes only 2 in the MALE flower) and in the morphology of leaf margins (very complete or slightly sinuate-dentees), these characters bringing this plant B. majungaensis Guillaumin. It should be pointed out, however, that the characters that define B. madecassa exist on plants mainly of dense rain forest, at the limit of the phytogeographical regions of the Center and the East (north and south of the island), and not in the West. The very typical arbuscular habit exists in both taxa. It may also be noted that the ramifications of the inflorescence, and often the common peduncle, are rather coral pink in B. madecassa, whereas a bright red color characterizes the same organs in B. majungaensis. Very curiously, we are led to report to this Madecassa, at least, provisionally, a southern population presenting a considerable disjunction area with the northern area.
Lineage
Parents
No parentage recorded.
Descendants
No recorded descendants.
Culture
No populated fields in this section.