Hilsenbergia capuronii 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 : 164-167

4. Hilsenbergia capuronii J.S. Mill. , sp. nov.

Arbor usque ad 15 m alta, cortice laevi, ramunculis puberulis vel glabris. Folia decidua, alterna; lamina elliptica usque obovata , 3-8(-11) cm longa, 1.5-4(-5) cm lata, apice acuta vel leviter acuminata , infrequenter obtusa , basi acuta usque obtusa , margine integra, minute revoluta , adaxialiter glabra vel sparse puberula, abaxialiter puberula vel glabra ; petiolo 0.5-2(-3) mm longo. Inflorescentiae terminale, cymosae. Flores bisexuales vel fortasse unisexuales; calyce campanulato, 3.5-4 mm longo, extus dense puberulo, intus dense albo pubescente; corolla urceolata vel tubularis. Fructus drupaceus, depresse-globosus, 6-8 mm longus, 8-10 mm in diam.; pyrenis 4, alatis.

TYPUS. — Miller et al. 10737, Madagascar, Prov. Toliara, Forêt d’Analalava , c. 14 km N of Route Nationale 7; west of Isalo National Park; east of the Malio River , deciduous forest on sand, 670 m, 22°35’26”S, 45°08’16”E, fr., 27 Jan. 2003 (holo-, MO!; iso-, P!, TAN!).

Tree to 15 m tall, to 25 cm dbh, bark smooth, greenish, whitish in the slash, trunk channeled, the twigs puberulent to glabrous; leaves deciduous, restricted to the current season’s growth, alternate; blades elliptic to obovate, the broadest point at or above the middle, 3-8(-11) cm long, 1.5-4(-5) cm wide, the apex acute or slightly acuminate, less commonly obtuse, the base acute to obtuse, the margin entire, minutely revolute, the adaxial surface glabrous or sparsely puberulent, evenly puberulent on the midrib and in a narrow band near the margin, the abaxial surface puberulent to glabrous, evenly puberulent on the midrib and secondary veins, evidently lighter in color than above, the venation brochidodromous, midrib impressed on the adaxial surface, raised on the abaxial surface, the secondary veins 5-7(-9), the tertiary veins reticulate; petioles 0.5-2(-3) cm long, evenly to sparsely puberulent, narrowly canaliculate on the adaxial surface.

Inflorescences terminal, cymose, to c. 3 cm long and up to 12-flowered, the branches puberulent. Flowers bisexual or possibly functionally unisexual, borne or pedicel-like branches 1-4 mm long; calyx campanulate, 3.5-4 mm long, 4-4.5 mm wide, 5-lobed, the lobes valvate, triangular, 1-1.5 mm long, densely puberulent on the exterior surface, densely white pubescent on the interior surface, the hairs evidently protruding from the calyx and visible with the naked eye; corolla urceolate or tubular with erect to spreading lobes, 4-5 mm long, 5-lobed, the lobes ovate, c. 1 mm long; stamens 5, the filaments 3-3.5 mm long, the upper 1.5-3 mm free, glabrous, the anthers ellipsoid to lanceoloid, 1-1.2 mm long; ovary conical, 1-3 mm long, 1.5-2 mm wide, the style 2-3 mm long, the 2 stigmas discoid or the style lacking an apparent stigmatic surface.

Fruits drupaceous, color at maturity unknown, borne in the persistent, spreading calyx, interior pubescence of the calyx clearly visible, depressed globose, 6-8 mm long, 8-10 mm in diameter, the endocarp bony, separating into 4 single-seeded pyrenes at maturity, the dorsal surface with parallel, papery wings. — Fig. 5 .

Hilsenbergia capuronii is very easily recognized by its bicolored leaves, which are relatively large among the Malagasy species, and the very distinctive pubescence on the interior surface of its calyx, easily visible in both flower and fruit. It is also unusual in having a densely puberulent midrib that is sunken into the surface of its leaves and also a thin band of pubescence along the upper leaf surface near the margin.

Hilsenbergia capuronii may be functionally dioecious. SF15736 has stamens with full, ellipsoid anthers inserted high in the corolla tube and a style that lacks any apparent stigmatic surface, whereas SF20594 has a gynoecium of normal appearance, but the stamens are inserted nearly at the base of the corolla and the anthers are somewhat smaller and lanceoloid. However, as this species is known from only three flowering specimens, only two of which have dissectable flowers, additional collections or field observations will be required to confirm this possibility.

This species is named in honor of René CAPURON (1921-1971) who was one of the most prolific students of Malagasy plants. He collected extensively in Madagascar for more than 20 years and contributed to the knowledge of many plant families. At the time of his death in 1971 he had been working to complete a study of woody Boraginaceae from Madagascar. He had taken extensive notes and had tentatively assigned names to many specimens. I have largely chosen not to accept CAPURON’ s names here as the numerous additional collections now available indicate that many of his provisional species were not correctly delimited. Furthermore, many of the epithets that CAPURON chose were based on geographic names and recent collections demonstrate that the species are more widespread than CAPURON’ s names would suggest. It is, however, most appropriate to pay tribute to one of the greatest students of Malagasy trees by naming this species, which he collected numerous times during his tenure with the Service Forestier, in his honor.

DISTRIBUTION. — Hilsenbergia capuronii occurs on sandy soil in southern Madagascar ( Fig. 6 ).

VERNACULAR NAMES. — Malamasafoy, Peha, Tanatananala.

CONSERVATION STATUS. — Provisional IUCN Red List Category: Endangered (EN B2ab(i-iv)). Hilsenbergia capuronii is know from a few scattered localities in southern and western Madagascar. Although its Extent of Occurrence is rather large, its Area of Occupancy is only 70 km 2 and Zombitsy National Park is the only protected area where its occurence has been recorded. In addition, other than a single individual tree that was collected in 2003, the species has not been collected for more than 30 years.

PARATYPES. — MADAGASCAR: Humbert 29577, Prov. Toliara, forêt de Zombitsy ( Sakaraha ), aux confins des bassins du Fiherenana et de l’Onilahy, forêt tropophile sur sables siliceux de l’Isalo, 600-850 m, 22°46’S, 44°42’E, ster., 26-29 Mar. 1955 ( P!) ; Leandri 2213, Prov. Mahajanga, forêt de Tsiampihy et forêts côtières près de Besaraha, de Bemiha, et de Soahanina, 0-20 m, 18°35’S, 44°14’E, fr., 20 Dec. 1952 ( MO!, P!) ; Service Forestier: SF574 (Capuron), Prov. Toliara, forêt d’Analamarina ( Hazoroa ) au SE de Sakaraha, 500- 600 m, 23°S, 44°34’E, fl., 28 Dec. 1961 ( MO!, P!) ; Service Forestier: SF4996 (Rasolofoson), Prov. Toliara, Hazoroa , Sakaraha , 500 m, 23°S, 44°36’E, fr., 21 Feb. 1952 ( P) ; Service Forestier: SF6851 (Capuron), Prov. Mahajanga, forêt de Tsienimpihy, à l’est du village de Besara, dist. Antsalova , 25 m, 18°35’S, 44°15’E, fr., 22 Dec. 1952 ( P!) ; Service Forestier: SF15348 (Poupon), Prov. Toliara, Ihera , Mahaboboka , 22°15’S, 44°16’E, fl., 2 Dec. 1955 ( P!) ; Service Forestier: SF15736 , Prov. Mahajanga, forêt de Ambararatakely, Mafaijijo, Maintirano , 25 m, 17 o 51’S, 45 o 21’E, fl., 21 Dec. 1955 ( MO!, P!, TEF!) ; Service Forestier: SF20594 (Capuron), Prov. Toliara, forêt d’Analamarina , Hazoroa , au SE de Sakaraha, 500-600 m, 23°S, 44°34’E, fl., 28 Dec. 1961 ( MO!, P!) ; Service Forestier: SF28947 (Capuron), Prov. Toliara, Sorita , crêtes et barres calcaires, au lieu-dit Ankiranja , à 30- 35 km de Manja, sur la route de Bevoay, 198 m, 21°28’S, 44°02’E, fl., 3-4 Dec. 1969 ( P!, TEF!) .

Figures

Fig. 5. — Hilsenbergia capuronii J.S. Mill.: A, flowering branch; B, whole flower attached to a piece of inflorescence; C, open calyx showing gynoecium; D, open corolla showing androecium; E, fruit, showing slightly expanded fruiting calyx; F, dorsal view of pyrene; G, cross-section of dorsal surface of pyrene. A-D, Service Forestier SF574; E, Service Forestier: SF4996 (Rasolofoson). Drawn by A. JOUY.

Fig. 6. — Distributions of Hilsenbergia species, mapped on the simplified bioclimate zones of Madagascar (after CORNET 1974; see SCHATZ 2000).