Nomenclature etc. MYIDSTICACEAE. Species included in the description: Horsfieldia amygdalina Warb. (1), H. brachiata (King) Warb. (1), H. bracteosa Hend. (1), H. flocculosa (King) Warb. (1), H. glabra (Bl.) Warb. (3), H. irya (Gaertn.) Warb. (2), H. lauterbachii Warb. (1), H. macrocoma (Miq.) Warb. (2), H. pilifera Markgraf (1), H. punctatifolia I.Sinclair (2), H. ralunensis Warb. (1), H. spicata (Roxb.) I.Sinclair var. sepikensis (Markgraf) I.Sinclair (1), H. succosa (King) Warb. (1), H. superba (Hook.f. & Thoms.) Warb. (1), H. sylvestris (Hott.) Warb. (2), H. trifida A.C. Smith (1), H. wallichii (Hook.f. & Thoms.) Warb. (2), Horsfieldia sp. (1). Not protected under CITES regulations.
Description based on 25 specimens. Tree. Geographic distribution: India, Pakistan, Sri Lanka, Thailand, Laos, Vietnam, Cambodia, and Indomalesia.
General. Growth ring boundaries distinct. Growth ring limits mostly demarcated by marginal parenchyma bands; in H. macrocoma and H. brachiata by bands of septate fibres. Heartwood basically brown, red, and yellow, without streaks. Sapwood colour similar to heartwood colour. Density 0.3–0.65 g/cm³. Heartwood pinkish to grey-brown, rarely red brown; wood with interlocked grain.
Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows and in clusters. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 65–157–270 µm; diameter of vessel lumina: large. Average number of vessels/mm² 2–4; vessels per square millimetre very few. Perforation plates simple and scalariform, with 5–10 bars. Perforation plates predominantly simple. Intervessel pits alternate, average diameter (vertical) 8–12 µm, medium and large, not vestured. Scalariform and opposite pitting occurs occasionally. Vessel-ray pits with distinct borders and with reduced borders or apparently simple, similar to intervessel pits and 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 not observed.
Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres very thin-walled and of medium wall thickness. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres septate and non-septate and non-septate. Septate fibres scattered near vessels and rays and arranged in parenchyma-like bands alternating with ordinary fibres. H. succosa: with thick-walled fibres in strictly radial rows.
Axial parenchyma. Axial parenchyma present, banded and not banded. Axial parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide and coarse, more than three cells wide. Axial parenchyma paratracheal. Paratracheal axial parenchyma scanty and vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 3–8. Unlignified parenchyma absent. H. brachiata + H. macrocoma: without marginal parenchyma bands.
Rays. Rays present, 4–10 per tangential mm, multiseriate (also if only few), (1–)2(–3) 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 commonly 500 to 1000 µm and commonly over 1000 µm. Rays composed of two or more cell types (heterocellular). Heterocellular rays with square and upright cells restricted to marginal rows, mostly 1 marginal row of upright or square cells and mostly 2–4 marginal rows of upright or square cells. Sheath cells absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent. H. spicata, H. sylvestris: with procumbent, square and upright cells mixed throughout the ray.
Storied structures. Storied structure absent.
Secretory structures. Oil and mucilage cells absent. Intercellular canals absent. Laticifers or tanniniferous tubes present.
Cambial variants. Included phloem absent. Other cambial variants absent.
Mineral inclusions. Crystals present and not observed, prismatic and needle-like (acicular), located in ray cells and axial parenchyma cells. Crystal-containing ray cells upright and/or square and 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. Cystoliths absent. H. brachiata, H. macrocoma: with acicular crystals in rays. Silica not observed.
Physical and chemical tests. Heartwood not fluorescent. Water extract fluorescent; basically colourless to brown or shade of brown. Heartwood extractives not leachable by water. Ethanol extract not fluorescent. Colour of ethanol extract colourless to brown or shade of brown. Chrome azurol-S test negative. Froth test negative. Splinter burns to partial ash. Ash white to grey.
Illustrations. • Transverse section. Horsfieldia sucosa. • Tangential section. Horsfieldia sucosa. • Radial section. Horsfieldia sucosa. • Tanniniferous tubes. Horsfieldia bracteosa. Horizontal tanniniferous tube (left); networking horizontal (in rays) and vertical (in axial parenchyma) tanniniferous tubes.
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’.