Nomenclature etc. NYSSACEAE. Species included in the description: Nyssa aquatica L. (2), Nyssa ogecheBatr. (1), Nyssa sylvatica Marsh (6). Not protected under CITES regulations.
Description based on 9 specimens. Tree. Geographic distribution: North America.
General. Growth ring boundaries distinct. Heartwood basically brown and white or grey, without streaks. Sapwood colour similar to heartwood colour. Odour indistinct or absent.
Vessels. Vessels present. Vessels arranged in diagonal and/or radial pattern and no specific pattern, in multiples, commonly short (2–3 vessels) radial rows, radial rows of 4 or more, and in clusters. Vessel outline angular. Two distinct vessel diameter classes absent. Average tangential vessel diameter 20–45–75 µm; diameter of vessel lumina: small to medium. Average number of vessels/mm² (50–)75–130(–200) (N. aquatica + N. sylvatica: 130–200 µm, N. ogeche: 50–75 µm); vessels per square millimetre numerous to very numerous. Perforation plates scalariform, with 20–30(–50) bars. 20–30 bars for N. aquatica and N. ogeche, often 50 and more bars in N. sylvatica. Intervessel pits opposite, average diameter (vertical) 4–6 µm, small, not vestured. Pit outline rectangular. Vessel-ray pits with distinct borders, different from intervessel pits, of uniform size or type, of the same type in adjacent elements, restricted to marginal rows. Helical thickenings absent. Tyloses in vessels absent. 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 common in both radial and tangential walls, distinctly bordered. Helical thickenings absent. Fibres non-septate.
Axial parenchyma. Axial parenchyma present, not banded. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse. Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per axial parenchyma strand (4–)6–10. Unlignified parenchyma absent.
Rays. Rays present, 10–14 per tangential mm, multiseriate (also if only few), 1–3 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 up to 500 µm. 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. Sheath cells absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent.
Storied structures. Storied structure absent.
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, located in axial parenchyma cells. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Crystal containing cells of normal size. 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 fluorescent. Colour of ethanol extract colourless to brown or shade of brown. Chrome azurol-S test negative. Froth test negative. Splinter burns to full ash. Ash bright white.
Illustrations. • Transverse section. Nyssa sylvatica. • Tangential section. Nyssa sylvatica. • Radial section. Nyssa sylvatica. • Miscellaneous. Nyssa sylvatica. Scalariform perforation plates and opposite intervessel pitting.
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’.