Humbertia

Accepted name/Authority/Place of publication:

HUMBERTIA Lam., Encyclopédie Méthodique, Botanique 2: 356 (1786)

Tribe:

Humbertieae

Synonyms:

Endrachium Juss., Genera Plantarum 133 (1789)

Smithia J.F. Gmel., Systema Naturae . . . editio decima tertia 2: 295, 388. (1791), non Smithia Aiton (1781)

Thouinia Sm., Plantarum Icones Hactenus Ineditae 7 (1789), nom. illeg. hom., non Thouinia Thunb. ex L. f., Supplementum Plantarum 9, 89. (1782) nec Thouinia Poit. Annales du Muséum National d'Histoire Naturelle 3: 70–71 (1804)

Type Species:

Habit:

Trees that can exceed 30 m in height and 2 m in diameter at the base, durable wood, yellow, hard, sinking in water (density of 1,280 kg/m, Bucur 2006) and with "a smell of sandalwood citrine" (fide Deroin 2001); young branches 2-3.5 mm in diameter, densely covered with reddish trichomes; older twigs glabrous, with very prominent leaf scars, bark light brown, grooved; lenticels indistinct.

Leaves:

Leaves with petiole 7-14 mm long, the blades obovate, leathery, 30-105 x 13-40 mm, the base wedge-shaped and long attenuate, the margins entire to sinuous, the apex obtuse or slightly emarginate; midrib canaliculate above, lateral veins 6-9 pairs.

Inflorescences:

Inflorescences terminal, thyrsiform, the lower bracts foliaceous; peduncles 7-11.5 mm long, the upper bracts deltoid, to 3 mm long or more, the pedicels 9-16 mm long, pubescent to glabrous.

Flowers:

Flowers medium-sized, somewhat zygomorphic or gibbous, with stamens and style curved; sepals subequal, 9-12 x 7.5-12 mm, the outer long ovate, rounded apically, the inner orbicular but cochleate, the apex emarginate, with wide scarious margins; corolla campanulate, slightly zygomorphic, about 15 mm long, the middle petal 18 mm long, the limb creamy white or peach-colored (McPherson 14267 MO), interplicae white-pilose without, the hyaline margins glabrous; stamens and styles exserted, the filaments subequal, ca 40 mm long, glabrous, inserted about 3 mm above the base of the tube, the bases long-triangular, grooved; anthers sagittate-rounded, ca 4.5 mm long; ovary campanuliform, 4 mm long, with erect trichomes on the upper half, with 2 locules, ± 20 ovules in the upper half; style ca 38 mm long, glabrous, the stigma short funnel-shaped, with 5 marginal lobes, the disc surrounding the base of the ovary.

Pollen:

Pollen almost spheroidal, smooth, 3-colporate (fide Pichon 1947).

Fruits:

Fruits baccate, ellipsoidal-ovoid, 12-17 mm long, apically depressed, surrounded by appressed sepals, these sometimes spreading, up to 12 mm long; pericarp indehiscent, leathery, brown, smooth, reticulate when dried, the disc obvious at the base of the fruit, surrounding a kind of gynophore.

Seeds:

Seeds 1-2, or up to 4 (fide Lamarck 1786:357), ovoid, ±7 x 6 x 4 mm, the integument tan, glabrous, deeply furrowed on the ventral face, with abundant albumen, the embryo and cotyledons oval.

Distribution:

Endemic to Madagascar. map

Countries:

Madagascar

Ecology:

Growing on ancient basaltic flows or sometimes on white littoral sands. The plants constitute an important emergent characteristic of a formation that extends along the entire east coast of Madagascar, the humid evergreen forest (Dumetz 1994. Schatz 2001).

Common names and uses:

The scarcity of Humbertia was caused by logging, which provides a distillation of sandalwood oil. The tree was regarded as nearly extinct by the end of the 19th century, but was rediscovered in 1946 by Henri Humbert (Humbert 20597 P). In Madagascar called bois de fer, endranendrana, fantsinakoha, fatsinakoha hendrahendrano, mera, or tesaka (Deroin 2001, Schatz 2001).

Phylogeny:

Stefanovic et al. (2002) made the assumption, perhaps correctly, that Humbertia was basal to the rest of the family Convolvulaceae in spite of several markedly distinct traits in these trees from the rest of the group. In making that assumption, they have done the same as several others. Their results are that Humbertia is most closely related to a clade containing several species typically placed in the Poraneae, and then to Erycibe of Asia. Later Stefanovic and Olmstead (2005) provided further molecular genetic evidence justifying the isolation of Humbertia within the Convolvulaceae. Clearly, the genus is distinct in many ways from the remainder of the family.

Number of Species:

References:

Bucur, V. 2006. Acoustics of Wood, Edition 2. Springer-Verlag, Berlin.

Deroin, T. 1992. Anatomie florale de Humbertia madagascariensis Lam. Contribution à la morphologie comparée de la fleur et du fruit des Convolvulaceae. Bulletin du Muséum national d'histoire naturelle. Section B, Adansonia 14(2) : 235-255.

Deroin, T. 2001. Convolvulaceae. Fl. Madagasc. 171 3–287.http://www.biodiversitylibrary.or/page/9503688#page/14/mode/1up

Dumetz, N. 1994. Sur les traces d'une forêt tropicale en voie d'extinction à Madagascar (l'ancienne forêt à Humbertia madagascariensis). Compt. Rend. Hebd. Séances Acad. Sci. 318: 1009–1014.

Humbert, H. 1948. Au suject de Humbertia madagascariensis Lamk., Notul. Syst. (Paris) 13: 303. http://www.biodiversitylibrary.org/page/7774310#page/593/mode/1up

Lamarck, J. B. P. A. de M. de 1783-1808. Encyclopédie méthodique: botanique. Paris,Panckoucke.

Mariaux A. 1959 Contribution a l'etude de Humbertia madagascariensis Lamk. II. Note sur le bois. J. Agr. trop. Bot. appl. 6. 616-19.

Pichon, M. 1947. Le genre Humbertia. Notul. Syst. (Paris) 13: 13–25. http://www.biodiversitylibrary.org/page/7774604#page/295/mode/1up

Pichon, M. 1951. Le fruit et la graine des Humbertiacées. Bulletin de la Société Botanique de France 98(7-8): 235-237.

Roberty, G. 1952. Genera Convolvulacearum. Candollea 14: 11–60.

Schatz, G. S. 2001. Generic Tree Flora of Madagascar. Royal Botanic Gardens, Kew, UK.

Schatz, G. E., S. Andriambololonera, Andrianarivelo, M. W. Callmander, Faranirina, P. P. Lowry, P. B. Phillipson, Rabarimanarivo, J. I. Raharilala, Rajaonary, Rakotonirina, R. H. Ramananjanahary, B. Ramandimbisoa, A. Randrianasolo, N Ravololomanana, Z. S. Rogers, C. M. Taylor & Wahlert. 2011. Catalogue of the Vascular Plants of Madagascar. Monogr. Syst. Bot. Missouri Bot. Gard. (in press).

Stefanovic, S. and R. G. Olmstead. 2005. Down the slippery slope: Plastid genome evolution in Convolvulaceae. Journal of Molecular Evolution 61: 292-305.

Author/Editor

Author:

Austin, D. F.

Publication:

Deroin, T. 2001. Convolvulaceae. Fl. Madagasc. 171: 3–287.

Contributors:

Convolvulaceae Unlimited

Convolvulaceae

Humbertia

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Humbertia

Author/Editor

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Humbertia

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