Wood Anatomy of the Subfamily Euphorbioideae

Abstract

The wood anatomy was studied of 82 species from 34 out of 54 genera in the subfamily Euphorbioideae, covering all five tribes recognized in this subfamily. In general the woods show a great deal of similarity. They are characterized by a relative paucity of vessels, often arranged in short to long, dumbbell-shaped or twin, radial multiples, and by medium-sized to large intervessel pits; fibres often have gelatinous walls; parenchyma apotracheal in short, wavy, narrow bands and diffuse-in-aggregates; mostly uni- or only locally biseriate rays, strongly heterocellular (except Hippomane, Hura and Pachystroma ). Cell contents, either silica or crystals, or both together, are nearly always present and often useful in distinguishing between genera. Radiallaticifers were noticed in most genera, though they are scarce and difficult to trace. The laticifers are generally not surrounded by special cells, except in some genera of the subtribe Euphorbiinae where radiallaticifers are comparatively frequent and conspicuous.