Wood anatomy of the dicotyledons indigenous to New Zealand 14. Piperaceae

Abstract

Abstract The anatomy of the secondary xylem of Macropiper excel sum (Forst.f.) Miq. is described. The wood is diffuse-porous with indistinct to very poorly defined rings. Vessels are solitary, in tangential pairs, in short radial multiples, and sometimes in small clusters. They are often storied, and have simple, transversely oriented perforation plates. Intervascular pits are mainly scalariform. Extremely fine spiral thickening is sometimes present. Pits leading to rays are bordered, and radially or obliquely elongated. Axial parenchyma is slightly to moderately frequent, mainly vasicentric, and often storied. Each parenchyma strand consists of 2–5 cells, but fusiform cells are also present. Rays are heterogeneous with their components intermingled. They are very large; usually 10–54 cells wide. Dissected rays are frequent. Sometimes fibres show a tendency towards a storied arrangement. Simple to slightly bordered pits are present mainly on radial walls. Septa are present in some fibres. Storied axial parenchyma and scalariform intervascular pits make an unusual combination of specialised and primitive features in M. excelsum wood.