Geniostoma stenocarpum A.C.Sm.
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Authority
Smith, Albert C. & Stone, Benjamin C. M. 1962. Studies of Pacific Island Plants, XVII: The Genus Geniostoma (Loganiaceae) in the New Hebrides, Fiji, Samoa, and Tonga. Contr. U. S. Natl. Herb. 37, Part I: 1-41; plates 1-3.
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Family
Loganiaceae
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Scientific Name
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Type
Type locality: Nandarivatu, Viti Levu, Fiji; the type, Degener & Ordonez 13591, is cited below [see Objects].
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Description
Description - Shrub or small tree to 4 m. high, with at first often minutely pubescent but soon glabrate slender subterete branchlets; stipules intrapetiolar, forming a short rounded sheath; leaves petiolate, the petioles 2-6 mm. long, the blades lanceolate or narrowly ovate, 4-7.5 cm. long, 1.2-2.7 cm. broad, attenuate and decurrent or merely acute at base, or very rarely subtruncate, narrowly acute to slightly acuminate at apex, entire, the costa slightly sulcate above, raised beneath, the lateral nerves 4-7 per side, prominulent, the veinlets mostly obscure; inflorescences glabrous or sometimes at first minutely pubescent and soon glabrate, axillary among the leaves, 5-12(-18)-flowercd, dichasial, compound dichasial, or often irregular, the peduncle 1 mm. long or less, the major axes 3-6 mm. long, the nodes bibracteate (sometimes with only 1 or with no bract), the pedicels 2-5 mm. long, bracteolate, the bracteoles about 0.5 mm. long; calyx cupuliform, the lobes deltoid-ovate, acute or short-acuminate, 1-3-nerved, the margins ciliolate; corolla short-tubular, 2.5-3.5 mm. long, glabrous externally, divided to middle, the tube glabrous within basally, sparsely hirtellous at throat with trichomes about 0.4 mm. long, similarly hirtellous in a narrow median horizontal band and on filaments (but glabrous between filaments in upper portion), the lobes ovate, glabrous, the venation relatively complex, each corolla-lobe supplied by 3 nerves with several lateral branches in the lobe, derived from a single main nerve entering the tube and producing two main lateral nerves in the throat; stamens inserted at throat, the filaments narrowly deltoid-ligulate, about 0.6 mm. long, pilose, the anthers glabrous except at extreme base, obtuse or with a minute mucronulato apex, ovate-oblong, 0.8-0.9 mm. long; ovary glabrous, subglobose, about 1 mm. in diameter, the style filiform, glabrous, short to nearly obsolete, 0.3-0.7 mm. long, the stigma subglobose, about 0.5 mm. in diameter, papillate; capsule ellipsoid, 7-10 mm. long, 2.5-3.5 mm. wide, apiculate by the stylar remnant, subtended basally by the persistent calyx.
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Discussion
The available specimens fall into three fairly well marked forms that appear not significant enough to merit names: a narrow-leaved glabrous form, a narrow-leaved puberulent form, and a glabrous form with comparatively broad, ovate leaf-blades. The first of these includes the type collection and most of the cited specimens. Only three collections (Degener 14314 and Gillespie 2941 and 4280) show a marked and fairly persistent puberulence on the branchlets; a minute indument is frequent on the innovations but is usually soon lost. One puzzling specimen, Smith 6020, seems to have both glabrous and persistently puberulent branchlets on one tree. The third form, with leaf-blades ovate and rounded to subtruncate at base, is represented by Gibbs 555 and Smith 5394. Association of these three forms with particular habitats or altitudes does not at this time seem to be noteworthy. The closest relationship of G. stenocarpum appears to be with G. rupestre, of the New Hebrides, and less notably with G. insulare. The small and predominantly lanceolate leaf-blades give a very distinct aspect to G. stenocarpum. Although corolla-lobe venation is not an entirely dependable criterion of relationship, in this respect G. stenocarpum is closer to G. insulare than to G. rupestre, in which the lobe-supplying nerve usually divides at or near the base of the corolla-tube. The flowers of G. stenocarpum are noted as foetid only by Gibbs, whose No. 555 is a mixture with G. vitiense; her comment may apply to the latter species, which is reported by various collectors as having malodorous flowers.
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Common Names
mbati-mbati, mbuimbuita, mbatimara