Hilsenbergia schatziana J.S. Mill., 2003

Miller, James S., 2003, Classification of Boraginaceae subfam. Ehretioideae: Resurrection of the genus Hilsenbergia Tausch ex Meisn., Adansonia (3) 25 (2), pp. 151-189 : 185-188

17. Hilsenbergia schatziana J.S. Mill. , sp. nov.

Arbor 10-15 m alta, ramunculis glabris. Folia decidua, alterna; lamina elliptica , (3.5-)5-9(-16) cm longa, 2.4-5.5(-7.5) cm lata, apice acuta usque acuminata , basi cuneata vel acuta usque obtusa , margine integra, utrinque glabra . Inflorescentiae terminale vel subterminale, cymosae, 3-7 cm latae. Flores bisexuales; calyce campanulato, 5-6 mm longo, 5-lobo, extus glabro, intus tomentoso; corolla alba , campanulata , c. 7 mm longa. Fructus drupaceus, depresse-ovoideus, 9-12 mm longus, 9-12 mm in diam.; pyrenis 4, alatis.

TYPUS. — Service Forestier: SF11302 (Capuron) , Madagascar, Prov. Antsiranana, massif de la Montagne d’Ambre, bassin de la rivière des Makis, 600 m, 12°37’S, 49°09’E, fl., 13 Oct. 1954 (holo-, P!; iso-, MO!, P!, TEF!) .

Tree 10-15 m tall, the twigs glabrous. Leaves deciduous, alternate; blades elliptic, the widest point near or just below the middle, (3.5)5-9 (-16) cm long, 2.4-5.5(-7.5) cm wide, the apex acute to acuminate, the base cuneate or acute to obtuse, the margin entire, both surfaces glabrous, the venation brochidodromous, the midrib even with or slightly impressed in the adaxial surface, raised on the abaxial surface, the secondary veins 4-6, the tertiary venation reticulate; petioles (1-)2-4(-6) cm long, glabrous, canaliculate on the adaxial surface.

Inflorescences terminal or subterminal, cymose, 3-7 cm broad, the peduncles 1-2.5 cm long, glabrous, bracts lacking. Flowers bisexual; calyx campanulate, 5-6 mm long, 6 mm wide, 5- lobed, the lobes deltate to triangular, 2.3-3 mm long, glabrous on the outer surface, tomentose on the inner surface; corolla white, campanulate, c. 7 mm long, c. 7 mm wide, 5-lobed, the lobes widely ovate, c. 2 mm long, c. 2 mm wide; stamens 5, the filaments 5 mm long, the upper 2-2.5 mm free, glabrous, the anthers ellipsoid, 2 mm long; ovary ovoid, c. 2 mm long, c. 2 mm wide, the style 3 mm long the 2 stigmas capitate.

Fruits drupaceous, borne in the 6-9 mm broad persistent calyx, depressed ovoid, 9-12 mm long, 9-12 mm in diameter, the endocarp bony, separating into 4 pyrenes at maturity, these 8-9 mm long, c. 4 mm wide, with papery wings on the exterior face. — Fig. 17 .

Hilsenbergia schatziana is apparently a substrate specialist restricted to northern Madagascar and is distinct from other members of the genus in its large fruits, glabrous leaves, c. 7 × 7 mm corolla, and in lacking bracts in its inflorescence. It is named in honor of my colleague George SCHATZ, a leading authority on the flora of Madagascar, who’s guide to the woody plant genera, and numerous other publications, have contributed so much to our understanding of the systematics and evolution of Malagasy plants.

DISTRIBUTION. — Hilsenbergia schatziana is known from only four collections, all from northern Madagascar ( Fig. 14 ). It may be restricted to basalt.

CONSERVATION STATUS. — Provisional IUCN Red List Category: Endangered (EN B2ab(i-iv)). Hilsenbergia schatziana is known from only two populations in northern Madagascar, one of which occurs within Montagne d’Ambre National Park, and it has not been collected for nearly 50 years.

PARATYPES. — MADAGASCAR: Service Forestier : SF7210 , Prov. Antsiranana, forêt d’Ambre, 12°37’S, 49°09’E, fr., 26 Mar. 1953 ( K!, MO!, P!, TEF!) ; Service Forestier: SF11276 (Capuron), Prov. Antsiranana, massif de la Montagne d’Ambre, 1000 m, 12°37’S, 49°09’E, fl., 8-14 Oct. 1954 ( K!, MO!, P!) ; Service Forestier : SF27741 (Capuron), Prov. Antsiranana, table basaltique d’Ambanitazana, près d’Andrapengy, au nord d’Antalaha, 14°40’S, 50°12’E, fr., 11 Apr. 1967 ( G!, GH!, K!, MO!, P!, TEF!, WAG!) .

Figures

Fig. 17. — Hilsenbergia schatziana J.S. Mill.: A, fruiting branch; B, whole flower; C, flower with opened corolla showing androecium and gynoecium; D, whole fruit with persistent calyx; E, dorsal surface of pyrene; F, cross-section of dorsal surface of pyrene. Service Forestier: SF27741 (Capuron). Drawn by A. JOUY.

Fig. 14. — Distributions of Hilsenbergia species, mapped on the simplified bioclimate zones of Madagascar (after CORNET 1974; see SCHATZ 2000).