Megistostegium microphyllum Hochr.

Koopman, Margaret M., 2011, A synopsis of the Malagasy endemic genus Megistostegium Hochr. (Hibisceae, Malvaceae), Adansonia (3) 33 (1), pp. 101-113 : 108-110

Megistostegium microphyllum Hochr.

Annuaire du Conservatoire et du Jardin botanique de Genève 18-19: 226-227 (1915). — Holotype: Madagascar. Toliara, Sud-Ouest: Dunes-Côte Mahafaly (Menaran-

dra), VI.1910, Perrier de la Bâthie 5471 (= Hochreutiner 13) ( G) .

ADDITIONAL MATERIAL EXAMINED. — Madagascar. Prov. Toliara, Beloha. Western slopes of La Table, c. 16 km from Toliaria on RN7, 23°23’S, 43°47’E, 12. I .2007, D. Baum & R . Ranaivojaona 382 ( MO). — Road from Toliara to St. Augustin , 1 km N of La Mangrove, 9 km from RN7, 23°27’S, 43°46’E, alt. 20 m, 14. I .2007, D. Baum & R . Ranaivojaona 388 ( MO). — Ambovombe ( Sud ), 2.XI.1960, J . Bosser 10180 ( MO). — Sud-Ouest : Environs du Cap Ste Marie, 2.III.1959, R . Capuron 11747 ( MO). — Environs du Cap Ste Marie, 2.III.1959, R . Capuron 11864- SF ( P). — Sud: Cap Ste Marie et abords immédiats, 28. I .1967, R . Capuron 22563- SF ( P). — 8-16 km E of Toliara on road to Tana , forested slopes, alt. 50 m, 8.II.1979, T. B . Croat 30955 ( MO). — 23- 28 km W of Manambaro , along RN10, alt. 50-60 m, 22.II.1979, T. B . Croat 31982 ( MO). — Ambovombe ( Behara ), 2.IX.1935, R . Decary 8381 ( MO). — Ikonka , 1.II.1935, R . Decary 9595 ( MO). — Kotoala au sudouest d’Ambovombe , dunes anciennes, 6.VIII.1935, R . Decary 9089 ( MO, P). — Côte sud-est, 2.II.1959, B . Descoings 607 ( MO). — Sud-Cap Sainte Marie-Faux Cap , 20.II.1961, B . Descoings 2529 ( MO). — RN7 , 35.6 km E of Tulear , spiny forest on calcareous plateau, 23°32’S, 43°93’E, 22.III.1989, L. J . Dorr et al. 4110 ( MO). — RN7 , 20.7 km E of Tulear , E of the “Table”, 23°38’S, 43°82’E, alt. 100-200 m, 26.III.1989, L. J . Dorr et al. 4146 ( MO). — RN7 , 23.1 km NE of Tulear , 23°22’S, 43°50’E, alt. 200 m, 27.III.1989, L. J . Dorr et al. 4165 ( MO). — 8 km N of Cap Ste Marie , 25°33’S, 45°08’E, alt. 210 m, 4.II.1989, B . Du Puy et al. MB64 ( MO). — SW Madagascar, near village of Ankoraroka, 26 km east of Toliara on RN7, 23°22’S, 43°51’E, alt. 200 m, 29. I .1993, B . Du Puy et al. MB30 ( MO). — Préfecture de Tôlanaro (Fort-Dauphin). — Cap Ste Marie ; roche calcaire, 25°34’S, 45°09’E, 27. I .1994, N . Dumetz 1245 ( MO). — Au sud d’Amovombe, sur les dunes au bord de la mer, 4. I .1904, M . Keraudren 961 ( MO). — 10 km E of Ambosary on the road to Fort Dauphin , 25°00’S, 46°27’E, alt. 120 m, 15.II.1997, M . Luckow 4129 ( MO). — La Table de Tulear, 23°20’S, 43°40’E, alt. 20 m, 15.IV.1975, D. Mabberley 935 ( MO). — Fort Dauphin region , W of town and E of Amboasary Sud , c. 7 km, along road to Lac Anony, 25°03’S, 46°28’E, alt. 20 m, 30. I .1994, G . McPherson & M . Pidgeon 14961 ( MO). — Route d’Ifotaka à Ambosary , 2.IV.1976, P . Morat 3959 ( MO, P). — Sud-Ouest: côte Mahafaly (Menarandra), 2. VI .1914, H . Perrier de la Bâthie 5471 ( P). — Cap Ste Marie Reserve , SW of Tsiombe, 25°35’S, 45°09’E, alt. 200 m, 28.XII.1987, P. B . Phillipson 2998 ( MO). — Valley of the Menarandra S of Ampanihy, N side of valley, 50 km from Ampanihy , opposite Marolinta, 25°04’S, 44°37’E, alt. 150 m, 26.II.1994, P. B . Phillipson & J. R . Milijaona 3629 ( MO). — Beloha, Lavanono , forêt épineuse à Euphorbiaceae , 25°16’S, 45°00’E, alt. 43 m, 25.XI.2006, R . Ranaivojaona et al. 530 ( MO). — Fourré xérophile d’Andatabo, à 20 km au S-SE de Tuléar , bord de la RN7, 23°24’S, 43°46’E, alt. 50-100 m, 7.II.2003, R . Randrianaivo et al. 328 ( MO). — On the road to St. Augustin, S of Toliara, c. 3-5 km from St. Augustin , 23°32’S, 43°46’E, alt. 0-100 m, 18.II.2002, S. G . Razafimandimbison 285 A ( P, MO, TAN). — Environs de Tulear , K. A . Richey 26 ( P, MO). — Cap Ste Marie Special Reserve , 300 m W of lighthouse, 25°35’S, 45°07’E, alt. 190 m, 18.II.1994, G. E . Schatz 2967 ( MO). — 14 km E of Toliara ( Tulear ) along RN7, 23°24’S, 43°47’E, alt. 100 m, 13.XII.1992, G. E . Schatz & J. S . Miller 2461 ( MO). — Just S of La Table, Tuléar, west side of road, alt. 100 m, 22.III.1992, T . Willing 71 ( MO) .

DESCRIPTION

Shrub 0.5-4 m tall. Leaves small (0.5-1.8 × 0.4- 1.3 cm), succulent, glabrous to shortly tomentose, gray-green to bright green elliptical to orbicular, clustering on short shoots, branches that are often naked at terminals (perhaps in response to current or past herbivore predation ( Bond & Silander 2007)). Stipules early caducous and minute. Flowers erect. Epicalyx cylindrical, orange/red, tips acuminate. Corolla light green to light pink, forms a tight cup that tapers at its lip, tightly hugging the staminal column that extends past the corolla 1.5-3 cm ( Fig.1 ). Pollen purple when fresh, average diameter of 107 µm with approximately 80 long echinae with a wide, “witch hat” base (14.8 µm tall × 8.8 µm wide at base) and approximately 141-1.8 µm wide apertures.

DISTRIBUTION AND ECOLOGY

Megistostegium microphyllum follows the distribution of M. nodulosum closely, known from Amboasary in the south to Toliara in the west, but never getting to the extreme northern localities of M. nodulosum ( Fig. 2). Megistostegium microphyllum is adapted to a variety of soil depths, for example at CSM ( Fig. 2) this species grows at soil depths of 0-36.2 cm. This species blooms over the entire year but primarily from the end of December through March (with single collections from the following months: June, August, September and November).

REMARKS

Ethnobotany

A powder of the bark is used to relieve eye ailments and a decoction of the leaves, twigs and bark is used as a pharmaceutical wash, a remedy for stomach aches, fatigue and as a means to expel the placenta after giving birth (ethnobotanical uses listed in this paper were assembled through interviews in Malagasy with local people with the help of T. A. Raveloarison). Branches are often used to decorate houses during the Christmas season and Antandroy children enjoy the nectar as a sugar source (pers. obs.).

Vernacular names

Tsomotsoy.

CONSERVATION STATUS

Megistostegium microphyllum lies within and outside the boundaries of protected areas throughout its range in southern Madagascar and will likely be subject to increasing population decline in coming years. In the span of one year, a healthy population of this species was extirpated close to St. Augustin near Toliara (pers. obs.). Furthermore , the species is well known for its medicinal properties and is frequently used in this regard. Given these threats, a preliminary (not yet submitted to IUCN /the Madagascar Red List authority) conservation designation of Vulnerable ( A4 c) IUCN (2001) is given to the species; a 30% total population reduction is estimated within three generations (45 years) .

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.