Elachyptera
Description
Lianas, shrubs or slender trees with scandent branches, glabrous except for parts of the inflorescence; branches (sub)opposite. Inflorescences axillary or terminal, densely flowered, paniculate-corymbose often super-numerary branches in the axils; peduncle and branchlets almost quadrangular. Flowers minute, congested; sepals 5, imbricate; petals 5, suberect; disk shortly cylindrical, erect, the rim often thickened, with short pointed extensions between the stamens; stamens 3, suberect; filaments membranous, ligulate, hardly broadened towards the base, anthers dehiscing by transverse, confluent clefts; ovary deeply sulcate, trilobed, ovules 2 per locule, collateral, style ending in a minute, capitate, triangular stigmatic shield or stigmas obscure. Fruits several per infructescence. Mericarps 3, divergent, separately attached to the slightly swollen receptacle; seeds affixed by a membranous wing that continues distally as a more or less widened flange around the embryoniferous part, the wing always shorter than the latter part.
Distribution
Africa present, Guianas present, Neotropics present, tropics of America present
7 species in the tropics of America and Africa, 3 of which occur in the Neotropics, 1 in the Guianas.
Wood
Growth rings faint, indicated by a narrow zone of radially compressed fibres.
Vessels diffuse, solitary, 11(8-14) per sq. mm, roundish, of two diffe- rent sizes, narrow vessels 40-60 μm diameter, wide vessels 80-200 μm. Vessel-member length: 690 (520-800) μm. Perforations simple. Inter- vascularpits alternate to opposite, elongate, slits often confluent giving a striate appearance, 3-5 μm. Vessel-ray pits as the intervascular pits. Rays uni- and multiseriate, up to 25 cells wide, 5-8 per mm, of which one wide. The uniseriates composed of tall upright cells, 2-12 cells high, the wide rays mainly of procumbent cells intermingled with square cells of irregular size as seen on tangential section, 450 μm wide, up to over 750 cells(= 1200 μm) high. Rhombic crystals present. Parenchyma scarce, diffuse and scanty paratracheal. Strands of 5-7 cells.
Ground tissue of fibre-tracheids and septate fibres. Fibre-tracheids lumen c. 13 μm, walls 3 μm, small bordered pits numerous on both radial and tangential walls. Septate fibres rather scarce, scattered amongst the fibre-tracheids, lumen slightly larger, walls 2 μm. Pits with minute borders mainly on the radial walls. Length fibre-tracheids: 1090(970-1200) μm. FIV ratio: 1.58.
Vessels diffuse, solitary, 11(8-14) per sq. mm, roundish, of two diffe- rent sizes, narrow vessels 40-60 μm diameter, wide vessels 80-200 μm. Vessel-member length: 690 (520-800) μm. Perforations simple. Inter- vascularpits alternate to opposite, elongate, slits often confluent giving a striate appearance, 3-5 μm. Vessel-ray pits as the intervascular pits. Rays uni- and multiseriate, up to 25 cells wide, 5-8 per mm, of which one wide. The uniseriates composed of tall upright cells, 2-12 cells high, the wide rays mainly of procumbent cells intermingled with square cells of irregular size as seen on tangential section, 450 μm wide, up to over 750 cells(= 1200 μm) high. Rhombic crystals present. Parenchyma scarce, diffuse and scanty paratracheal. Strands of 5-7 cells.
Ground tissue of fibre-tracheids and septate fibres. Fibre-tracheids lumen c. 13 μm, walls 3 μm, small bordered pits numerous on both radial and tangential walls. Septate fibres rather scarce, scattered amongst the fibre-tracheids, lumen slightly larger, walls 2 μm. Pits with minute borders mainly on the radial walls. Length fibre-tracheids: 1090(970-1200) μm. FIV ratio: 1.58.