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doi:10.1006/bojl.1994.1060 | How to Cite or Link Using DOI
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Wood and bark anatomy of Gnetum gnemon L.
Sherwin Carlquist F.L.S.
Santa Barbara Botanic Garden, 1212 Mission Canyon Road, Santa Barbara, CA 93105, U.S.A.
Available online 26 April 2002.

Abstract

Quantitative and qualitative data are presented for seven collections representing two varieties (unlike in habit) ofGnetum gnemon. Tracheids are present, but abundant and intermixed with them are septate fibre-tracheids rich in starch. Axial parenchyma has been reported only once previously for the species. Axial parenchyma is in strands of 4-10 cells, is rich in starch, is primarily vasicentric (paratracheal) in distribution, less commonly diffuse. About equally common are simple and compound perforation plates; the latter are composed of from two to about ten bordered foraminate perforations, the shape of which may be altered by crowding or coalescence, but is clearly still foraminate. Lateral walls of vessels bear pits that are vestured around pit cavities, not facing the pit membrane. Rays are composed mostly of procumbent cells; the tangential walls bear bordered pits. Crystals, present in ray cells and (rarely) axial parenchyma vary widely in size. Crystalliferous sclereids with layered walls, starch-rich parenchyma, and gelatinous secondary phloem fibres are the main components of bark. Early stages in origin of successive vascular cambia in bark are newly described. When representative conditions are derived from study of large numbers of slides, the classical view that Gnetum vessels are unlike those of angiosperms is supported. Features of Gnetum gnemon wood are discussed in the light of ecology and conductive physiology.
Keywords: —angiosperm evolution ecological wood anatomy Gnetales - gymnosperms - successive cambia - variant wood structure
 

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