New Species of Hedyosmum (Chloranthaceae) from Northern South America

Abstract

Four new species of Hedyosmum, all belonging to subgenus Tafalla sect. Microcarpa, are herein proposed. Hedyosmum uniflorum occurs in mid-elevation montane regions in central Ecuador and differs from its closest relative, H. bonplan- dianum, by its basally rounded, sometimes oblique leaves, flocculose midveins, slightly fimbriate stipular appendages, and long, linear, dissected stigmas. Hedyosmum narinoense, which inhabits the western slopes of the western cordillera in southern Colom- bia, also has single-flowered cymules but is unique among the solitary-flowered cymule species by hav- ing shorter pistillate inflorescences and scabrous, scurfy leaf sheaths. The remaining two new species, H. tepuiense and H. intermedium, are found in the Venezuelan Guayana. Hedyosmum tepuiense is rec- ognized as distinct from the broadly ranging H. racemosum by virtue of its long stipular appendages, verrucose leaf sheaths, floccose midveins, and longer inflorescences. Morphologically intermediate be- tween H. gentryi and H. neblinae, Hedyosmum intermedium is distinguished by its glabrous, elliptic leaves and 2-3-flowered purple-fruited cymules. tall; young stems quadrate; older stems terete, with tubular leaf bases persisting, ultimately disintegrat- ing and leaving circular scars; internodes 3-8 cm long. Leaves elliptic, 7.5-15.5 cm long, 3-6.5 cm broad, with long-acuminate tips 0.5-1 cm long, rounded, often oblique at base, at margins sharply serrate with teeth 3-4 mm distant, drying subcor- iaceous, smooth to slightly scabrous; midveins im- pressed above, raised beneath, with sparse floccose multibranched trichomes; larger lateral veins 6-9, 0.6-1.8 cm distant, arcuate, raised beneath, gla- brous or occasionally with sparse strigose to floc- culose hairs; free portion of petioles 0.6-1.4 cm long, glabrous except for occasional flocculose hairs running down midrib onto petiole; petiolar sheaths 1.3-1.8 cm long, 0.5-1 cm broad at apex, inflated, slightly flared at apex, with two strigose lines ex- tending down from the free portion of petioles, per- sistent but disintegrating with age, each distal margin with two slightly fimbriate, stipular appendages 1- 2 mm long, extending above free portion of petioles ca. 0.5 mm. Staminate inflorescences not seen. Pis- tillate inflorescences axillary or terminal, racemes or sparsely branched panicles, 3.5-8 cm long with 16-46 cymules; subtending bracts similar in size and shape to the leaves or more frequently smaller; cymules l(-3)-flowered, alternately or oppositely ar- ranged on the rachis, 3-10 mm distant, sessile or on short peduncles 1-3 mm long; subtending floral bracts enclosing one-fourth to three-quarters of flow- er, with acuminate tips 0.5-1 mm long, margin entire or with occasional strigose hairs. Pistillate flowers slightly trigonous, ca. 3 mm long, ca. 2 mm broad, with or without a small pore on each face of the ovary; perianth lobes small, deltoid; stigmas usu- ally highly dissected, linear, 2-3 mm long, papillose. Fruiting cymules green (?).