Euplassa
Content
Description
Trees, less frequently shrubs. Leaves spirally arranged, paripinnate, rhachis frequently ending in a terminal appendix extending up to 2 cm beyond terminal leaflet pair, rarely forming a terminal leaflet; leaflets 2-10 pairs, opposite to strongly subopposite, subsessile to long-petiolate, shape various, basal pair consistently smaller than rest; margin entire to remotely serrate. Inflorescences generally unbranched, pseudo-racemose, axillary or rarely terminal, solitary, occasionally with 2 inflorescences per leaf axil; flowers in pairs, each pair supported by a peduncle of variable length which is frequently altogether absent; each pair subtended by a small common bract; flowers sessile or pedicellate. Flowers weakly zygomorphic; tepals all recurving at anthesis or one (innermost) remaining erect; stamens epitepalous, anthers ovate, subsessile, housed in concave distal end of tepals; hypogynous glands 4, fleshy, distinct, lobed or fused to form a quadrangular structure (or nectary disk); ovary subsessile, glabrous to densely pubescent, with 2pendulous, orthotropous ovules, style curved, stigma latero-apical. Fruit a nut or rarely a drupe, indehiscent, 1-2-seeded, subglobose to ovoid; outer mesocarp thin and coriaceous or thick and fleshy; inner mesocarp thin and woody or very thick and sclerous; seeds fleshy, more or less compressed, not winged.
Distribution
Bolivar endemic, E Brazil endemic, Guianas endemic, Neotropics endemic, SE Brazil endemic, Southern America: Bolivia (Bolivia endemic); Brazil South (Paraná endemic); Brazil Southeast (Minas Gerais endemic); Venezuela (Venezuela endemic), central Colombia endemic, tropical S America endemic
Endemic to tropical S America, ranging from Venezuela (Bolívar) and central Colombia, to SE Brazil and Bolivia, the center of distribution is in SE Brazil from Minas Gerais to Paraná; 20 species in the Neotropics of which 2 species are known to occur in the Guianas.
Wood
Growth rings indistinct or absent.
Vessels diffuse, solitary, paired or in groups of 3-4, rarely more, which tend to be tangentially arranged and occasionally appear as tangential bands; 3-14 (9) per mm2, circular 45-258 (148) μm wide. Perforation plates simple. Intervessel pits alternate and usually bordered. Vessel-ray pits alternate.
Rays uniseriate and multseriate (5-22 cells wide), 1-2 per mm. Uniseriate rays composed of square to upright cells and 1-2 cells in height. Multiseriate rays composed of predominantly procumbent body cells and 1-3 (extremely rarely up to 5) rows of upright and/or square marginal cells. Multiseriate rays 78-1100 (540) μm wide and over 1 mm in height, sometimes appearing as an aggregate, dissected by axial elements. Nested sclerotic ray parenchyma cells () can be present in the multiseriate rays along with amorphous (non crystalline) deposits.
Axial parenchyma present in narrow tangential bands 1-2 cells wide and 4-8 per mm, with 2 to many cells per strand. Ground tissue of non septate fibres with thin to thick walls and rare simple to minutely bordered pits on the radial walls.
Vessels diffuse, solitary, paired or in groups of 3-4, rarely more, which tend to be tangentially arranged and occasionally appear as tangential bands; 3-14 (9) per mm2, circular 45-258 (148) μm wide. Perforation plates simple. Intervessel pits alternate and usually bordered. Vessel-ray pits alternate.
Rays uniseriate and multseriate (5-22 cells wide), 1-2 per mm. Uniseriate rays composed of square to upright cells and 1-2 cells in height. Multiseriate rays composed of predominantly procumbent body cells and 1-3 (extremely rarely up to 5) rows of upright and/or square marginal cells. Multiseriate rays 78-1100 (540) μm wide and over 1 mm in height, sometimes appearing as an aggregate, dissected by axial elements. Nested sclerotic ray parenchyma cells () can be present in the multiseriate rays along with amorphous (non crystalline) deposits.
Axial parenchyma present in narrow tangential bands 1-2 cells wide and 4-8 per mm, with 2 to many cells per strand. Ground tissue of non septate fibres with thin to thick walls and rare simple to minutely bordered pits on the radial walls.