Commercial Timbers


H. G. Richter and M. J. Dallwitz

Phyllostylon brasiliensis Capanema (Baitoa)

Nomenclature etc. ULMACEAE. Syn.: Phyllostylon rhamnoides Taub., Samaroceltis rhamnoides Poisson. Trade and local names: San Domingo boxwood, West Indian boxwood (GB, US); baitoa, bois blanc (DO); bois blanc (HT); jatia (CU); seron, cerón (MX); membrillo (VE); pao branco (BR); palo lanza, p. blanco, p. amarillo, ibirá-catá, tala grande (PY, AR). Not protected under CITES regulations.

Tree. Geographic distribution: Caribbean.

General. Growth ring boundaries distinct or indistinct or absent. Growth ring limits microscopically distinct in some specimens by larger and more frequent vessels (earlywood), by thickened (noded) rays, and by darker fibrous zones (latewood). Heartwood basically yellow white or grey, without streaks. Sapwood colour similar to heartwood colour. Odour indistinct or absent. Density 0.82–0.92 g/cm³.

Vessels. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows to radial rows of 4 or more. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 20–45–65 µm; diameter of vessel lumina: small to medium. Average number of vessels/mm² 80–120; vessels per square millimetre numerous to very numerous. Average vessel element length 100–170–240 µm. Average vessel element length short. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 6–10 µm, small to medium, not vestured. Vessel-ray pits with reduced borders or apparently simple, similar to intervessel pits, rounded or angular, of uniform size or type, of the same type in adjacent elements, located throughout the ray. Helical thickenings absent. Tyloses in vessels rarely present or absent, thinwalled. Other deposits in heartwood vessels present, vessels frequently filled with amorphous mineral contents (calcium carbonate).

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness to very thick-walled. Average fibre length 300–820–1300 µm. Average fibre length short to medium. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma not banded. Axial parenchyma paratracheal. Paratracheal axial parenchyma scanty, vasicentric, aliform, and confluent. Aliform parenchyma winged. Axial parenchyma fusiform and as strands. Average number of cells per axial parenchyma strand 2(–4).

Rays. Rays 6–13 per tangential mm, multiseriate (also if only few), (1–)2–3(–4) cells wide, narrow (2–3 seriate). Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays absent. Rays of one size. Height of large rays up to 500 µm. Rays composed of a single cell type (homocellular); homocellular ray cells procumbent. Sheath cells absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent. Marginal rows occasionally formed by large procumbent cells.

Storied structures. Storied structure present, some rays storied, some not, axial parenchyma storied, vessel elements storied. Arrangement of tiers regular (horizontal or straight), or irregular. Number of ray tiers per axial millimetre 4–6. Storied structure often inconspicuous.

Secretory structures. Oil and mucilage cells absent. Intercellular canals absent. Laticifers or tanniniferous tubes absent.

Cambial variants. Included phloem absent. Other cambial variants absent.

Mineral inclusions. Crystals present, prismatic and in other forms, located in ray cells and axial parenchyma cells. Crystal-containing ray cells procumbent, upright and/or square ray cells not chambered. Crystals in procumbent ray cells not in radial alignment. Crystal-containing axial parenchyma cells not chambered. Number of crystals per cell or chamber one. Crystal containing cells of normal size. Cystoliths absent. Crystals in rays restricted to zones intersecting with growth ring boundaries. Silica not observed.

Physical and chemical tests. Heartwood not fluorescent. Water extract not fluorescent; basically colourless to brown or shade of brown. Heartwood extractives not leachable by water. Ethanol extract fluorescent. Colour of ethanol extract yellow or shade of yellow. Weak fluorescence, light yellow. Chrome azurol-S test negative. Froth test negative. Splinter burns to partial ash. Ash white to grey.

Illustrations. • Transverse section. Phyllostylon brasiliensis. Note characteristic calcium carbonate deposits in vessels. • Transverse section. Phyllostylon brasiliensis. • Tangential section. Phyllostylon brasiliensis. • Radial section. Phyllostylon brasiliensis. Inset: Characteristic calcium carbonate deposits in vessels.

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.’.