Nomenclature etc. EUPHORBIACEAE. Trade and local names: tapi'a guasu, chipa rupa (PY); tapiá, caixeta, tapia-guaçu, tapiá-mirim, folha-de-bolo, tamanqueira, canela-samambaia, malacaxeta, taneiro, canela-raposa, boleiro, chico-rupa (BR). Not protected under CITES regulations.
Description based on 3 specimens. Tree. Geographic distribution: southern Brazil.
General. Growth ring boundaries indistinct or absent. Heartwood basically brown (according to Mainieri & Péres Chimelo (1989) colour can also be light to pinkish beige), without streaks. Sapwood colour similar to heartwood colour. Odour indistinct or absent. Density 0.44 g/cm³.
Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows and radial rows of 4 or more. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 120–200(–250) µm; diameter of vessel lumina: large. Average number of vessels/mm² 2–10(–20); vessels per square millimetre few. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 13–17 µm, large. Vessel-ray pits with reduced borders or apparently simple, different from intervessel pits, rounded or angular and horizontal to vertical, of two distinct sizes or types in the same ray cell, of the same type in adjacent elements, located throughout the ray. Helical thickenings absent. Tyloses in vessels present, thinwalled. Other deposits in heartwood vessels present, amber coloured organic contents.
Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres very thin-walled. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres non-septate.
Axial parenchyma. Axial parenchyma present, not banded. Axial parenchyma apotracheal. Apotracheal axial parenchyma diffuse and diffuse-in-aggregates. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 4–7(–8). Unlignified parenchyma absent.
Rays. Rays present, 14–18(–22) per tangential mm, exclusively uniseriate. Aggregate rays absent. Rays of one size. Height of large rays commonly over 1000 µm (according to Mainieri & Péres Chimelo (1989) rays up to 4 mm high). Rays composed of two or more cell types (heterocellular). Heterocellular rays with square and upright cells restricted to marginal rows, mostly 2–4 marginal rows of upright or square cells and with more than 4 marginal rows of upright or square cells. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent. Biseriate rays only occasionally present.
Storied structures. Storied structure absent.
Secretory structures. Oil and mucilage cells absent. Intercellular canals absent. Laticifers or tanniniferous tubes present. This refers to so-called latex traces as desribed in IAWA (1989); these are large, dark coloured openings in some rays, albeit very infrequent.
Cambial variants. Included phloem absent. Other cambial variants absent.
Mineral inclusions. Crystals present, prismatic and druses, located in ray cells. Crystal-containing ray cells upright and/or square, upright and/or square ray cells not chambered. Number of crystals per cell or chamber one. Crystal containing cells of normal size. Cystoliths absent. The occurrence of two crystals of the same of different size in one cell is rather rare. Silica not observed.
Illustrations. • Transverse section. Alchornea triplinervia. • Tangential section. Alchornea triplinervia. • Radial section. Alchornea triplinervia. • Miscellaneous. Alchornea triplinervia. Exceptionally large intervessel pits, up to 17Ám in diameter. Large latex traces occasionally present.
The interactive key allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting specified attributes, summaries of attributes within groups of taxa, and geographical distribution.
Cite this publication as: ‘Richter, H.G., and Dallwitz, M.J. 2000 onwards. Commercial timbers: descriptions, illustrations, identification, and information retrieval. In English, French, German, Portuguese, and Spanish. Version: 25th June 2009. http://delta-intkey.com’.