Megistostegium nodulosum (Drake) Hochr.

Koopman, Margaret M., 2011, A synopsis of the Malagasy endemic genus Megistostegium Hochr. (Hibisceae, Malvaceae), Adansonia (3) 33 (1), pp. 101-113 : 110-112

Megistostegium nodulosum (Drake) Hochr.

Annuaire du Conservatoire et du Jardin botanique

de Genève 18-19: 228 (1915). — Basionym: Hibiscus

nodulosus Drake, Bulletin du Muséum national d’Histoire

naturelle Paris 9: 38 (1903). — Type: Madagascar, Faux

Cap, arbre de la brousse épineuse. 15 VII 1901, G .

Grandidier s.n. (P).

Macrocalyx tomentosa Costantin & Poisson, Comptes Rendus des Séances de l’Académie des Sciences Paris 147: 637 (1908). — Type: Madagascar, Tulear , Massif de la Table, F. Geay 5295, 5301 (P).

Macrocalyx tomentosa var. rubra Poisson, Recherches sur la flore méridionale de Madagascar: 27 (1912). — Type: Madagascar, plante en buisson à aspect de Rhododendron, fleur rouge, pentes arides au-dessus des grottes d’Andrahomena (Sud), Alluaud 19 (P).

Megistostegium retusum Hochr., Annuaire du Conservatoire et du Jardin botanique de Genève 18: 227 (1915). — Holotype: Madagascar, sud-ouest, dunes au sud du lac Tsimanampetsa ou Mananpetsa, VI.1910, Perrier de la Bâthie 5472 (= Hochreutiner 16) (G).

Megistostegium retusum fma. humbertii Hochr. nom. nud., in sched. Madagascar, environs de Tulear , delta de Fiherenana, lieux sablonneux, dunes, arbuste, fleurs rouge vif. 14-26.IX.1924, Humbert & Perrier de la Bâthie 2535 ( A, B, US) .

ADDITIONAL MATERIAL EXAMINED. — Madagascar. Prov. Efotsy (S-O), 2.III.1955, J . Bosser 53 ( MO). — Itampolo (S-O), 2.III.1955, J . Bosser 68 ( MO). — Route Betioky- Soalary , 2.II.1968, J . Bosser 19293 ( P, MO). — SW , Bush entre Atanadebo et Behara (aux confins des districts de Ft. Dauphin et Ambovombe), 29.IX.1957, R . Capuron 8535- SF ( P). — Route d’Ifaty Tulear , 31.VIII.1965, F . Chauvet 106 ( P). — Open woodland, 12 km N of Toliara on road to Morombe near sea level, 5.II.1975, T. B . Croat 30793 ( MO). — Au nord d’Ambatomainty Ambovombe, 30. I .1932, R . Decary 9591 ( P). — Haute vallée du Manambolo, 25.XI.1935, R . Decary 9406 ( P). — Behara (près de Fort Dauphin ), 11.VII.1930, R . Decary 4280 ( P). — Ambovombe ( Behara ), 10. I .1935, R . Decary 8379 ( P, MO). — Coastal plain, 12 km N of Toliara, on RN9, 1 km S of Tsangoritelo, 23°23’S, 43°63’E, 1.II.1994, B . Du Puy et al. MB580 ( MO). — SW , Province of Toliara (Tulear), NW of Toliara, Forest of Mikea , c. 13 km N of the mouth of the Manombo River, near the coast, 22°44’S, 43°20’E, alt. 30 m, 4.XII.1993, Du Puy et al. M692 ( MO, P). — Cultivated at the USDA plant introduction station, Miami FL P. I . No. 77929, introduced from south of Lake Tsimanampetsotsa ,by Charles Swingle and Henri Humbert, 22. I .1974, W. T . Gillis 8876 ( MO). — Environs de Tulear , coteaux calcaires (La Table), 8.VIII.1932, H . Humbert & C. F . Swingle 5208 ( P). — Environs de Tulear, delta du Fiherenana , lieux sablonneux, dunes, alt. 2-10 m, 14-26. IX.1924, H . Humbert & H . Perrier de la Bâthie 2535 ( P). — N coastal road out of Tulear, 35-50 km N (road to Morambe ) , 23°12’S, 43°37’E, alt. 0-20 m, 12.XI.1993, R. C . Keating & J. S . Miller 2242 ( MO). — Bevato Nord , 5.IX.1972, B . Koechlin s.n. ( P). — Bevato Nord sur calcaire et sable, 1967-1969, B . Koechlin s.n. ( P). — N of Toliara on coastal track between Manambo and Salary Forest , c. 3 km N of Tsifota village, 5.VIII.1997, B . Lewis 518 ( MO). — Toliara, approximately 15-20 km N of Ifotsy on the road to Beheloka , alt. 50 m, 2.II.2002, M . Luckow 4325 ( MO). — SW, P . Montagnac 130 ( P). — Soalara , 2.III.1908, P . Morat 672 ( P). — Entre Vohombe et Lambetamasay, 2. VI .1932, G . Petit s.n. ( P). — Réserve d’Andohahela, Parcelle 2; NE of Amboasary near Hazofotsy, 24°50’S, 46°32’E, alt. 100 m, 8.XII.1992, P. B . Phillipson 2842 ( MO). — R. N . X. Tulear , 12. I .1952, Ravelonjarahony 3637 ( P). — Near Songeritelo, N of Tuléar , 14 km N of Fiherenana River Bridge, on E side of road, 23°23’S, 43°37’E, 24.III.1988, T . Willing 74 ( MO). — 19 km E of Beloha on Tsihombe Road, Tulear , 25°17’S, 45°03’E, 4.XI.1989, T . Willing 8 ( MO) .

DESCRIPTION

Tree up to 8 m tall. Leaves well distributed along the entirety of the branches, gray-green, thin, flexible, orbicular (1.1-3.96 × 1.4-3.9 cm) with a distinctive cordate base and downy tomentum. Stipules filiform. Flowers erect. Epicalyx lobes somewhat rounded at the apex, light pink/red in color. Corolla red/pink and does not form a cup but instead has an open architecture in which petals do not overlap each other. Staminal column long, exserted past the corolla, up to 5 cm long, curved, making the flower zygomorphic in form ( Fig. 1 ). Pollen yellow when fresh, average diameter 110 µm with echineae 12.4µm tall × 7.8 µm wide and 2 µm wide apertures.

DISTRIBUTION AND ECOLOGY

Megistostegium nodulosum has the largest range of the three species, extending from north of Toliara in the west to north of Tranomaro near the transitional forest to the southeast ( Fig. 2). The species appears to be restricted to sandy habitats and at CSM grows in soils that average 34.87 cm (± 0.49) in depth. This species has been collected throughout the year but most collections are from November through mid-March, with a second peak in August through September (single specimens exist from June and July).

REMARKS

Ethnobotany

The strong wood of this species is used regularly for house construction (major structural beams), charcoal for cooking and as a torch by which to fish for lobster at night (pers. obs.). One mention is made of using the wood of Megistostegium nodulosum (as Macrocalyx tomentosa ; Costantin & Poisson 1908) for nails to assemble pirogues. A powder of the bark and branches are used in the same way as in the previous species.

Vernacular names

Vonkara,Tsomotsoy (Somontsoy),Tsomotsoy lahy, Sognogne.

CONSERVATION STATUS Megistostegium nodulosum has the widest distribution of the three species (EOO of c. 56000 km 2, and an AOO exceeding 2000 km 2) and resides inside three

protected areas. The current conservation status is deemed Near Threatened (NT), because populations will likely approach a 30% reduction in size over the next three generations, given current ethnobotanical practices and the fact that the species is highly sought after for its strong wood.

Figures

FIG. 1. — Floral and habit photographs of the three species of Megistostegium Hochr.: A, M. microphyllum Hochr.; B, M. nodulosum (Drake) Hochr.; C, M. perrieri Hochr. Scale bar for flowers: 2 cm.