Hilsenbergia angustifolia 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 : 158-160

1. Hilsenbergia angustifolia J.S. Mill. , sp. nov.

Arbor usque ad 7 m alta, cortice in laminas tenues exfoliante, ramunculis glabris vel minute puberulis. Folia decidua, alterna; lamina anguste-elliptica usque lanceolata , 6.5-10 cm longa, 1-3 cm lata, apice basique attenuata , margine integra, adaxialiter glabra vel sparsim minuteque puberula, abaxialiter sparsim puberula; petiolo 8-18 mm longo. Inflorescentiae terminale, cymosae, c. 3 cm latae. Flores non visi. Fructus drupaceus, flavo-aurantiacus, depresse globosus, 20-23 mm longus, 23-28 mm in diam.; pyrenis 4, alatis.

TYPUS. — Service Forestier: SF24122 (Capuron), Madagascar, Prov. Toliara, forêt très dégradée, sur sable, près d’Andrenialamahitsy, au nord du Lac Ihotry, 21°50’S, 43°40’E, fr., 27 May 1965 (holo-, P!; iso-, G!, K!, MO!, P!, TEF!) .

Tree 6-7 m tall, the bark exfoliating in plates, the twigs glabrous or minutely puberulent. Leaves deciduous, alternate; blades narrowly elliptic to lanceolate, the widest point near or below the middle, 6.5-10 cm long, 1-3 cm wide, the apex attenuate, the base attenuate, the margin entire, the adaxial surface glabrous to sparsely and minutely puberulent, the abaxial surface sparsely puberulent, the venation brochidodromous, the midrib impressed on the adaxial surface, raised on the abaxial surface, the secondary veins 8-13, the tertiary venation reticulate; petioles 8-18 mm long, sparsely puberulent, shallowly canaliculate on the adaxial surface.

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Inflorescences terminal, cymose, c. 3 cm broad, the branches glabrous. Flowers not seen.

Fruits drupaceous, yellow-orange at maturity, borne in the 7-11 mm broad persistent calyx, globose, 20-23 mm long, 23-28 mm in diameter, the endocarp bony, separating into 4 pyrenes at maturity, these c. 15 mm long, 8 mm wide, with parallel papery wings on the exterior surface. — Fig. 1 .

Hilsenbergia angustifolia is a very distinctive species easily recognized by its long, narrow leaves that are unlike any of the other large-fruited members of the genus.

DISTRIBUTION. — Hilsenbergia angustifolia is known from only a single collection made on sand north of Lac Ihotry in southwestern Madagascar ( Fig. 2 ).

C O N S E RVAT I O N S TAT U S. — Provisional IUCN Red List Category: Critically Endangered (CR B1ab(I-iv) + 2ab(I-iv)). Hilsenbergia angustifolia has been collected only once from a locality that the specimen label described as very degraded in 1965. It is questionable whether this species still survives.

Figures

Fig. 1. — Hilsenbergia angustifolia J.S. Mill.: A, Fruiting branch; B, fruiting calyx showing uneven separation of the five lobes; C, dorsal view of pyrene; D, cross-section of dorsal surface of pyrene. Service Forestier: SF24122 (Capuron). Drawn by A. JOUY.

Fig. 2. — Distributions of Hilsenbergia species, mapped on the simplified bioclimate zones of Madagascar (after CORNET 1974; see SCHATZ 2000).