Identification of Japanese species of evergreen Quercus and Lithocarpus (Fagaceae)

Abstract

To identify archaeological oak woods with very large vessels (> 200 μm), the wood structure of eleven species of evergreen Quercus and Lithocarpus from Japan were studied. Species groups could be identified by the size and frequency of vessels and the ray structure. Quercus phillyraeoides of subg. Sclerophyllodrys had semi-ring-porous wood with small (< 100 μm on average), numerous vessels, and aggregate rays. Two species of Lithocarpus had aggregate to semi-compound rays that came to be divided by the development of vertical masses of fusiform cells. Among species of Quercus subg. Cyclobalanopsis, Q. gilva, Q. hondae, and Q. miyagii had very large vessels with a maximum vessel diameter over 200 μm. Within the species groups, individual species could not be identified just from wood structure, but Q. gilva could be distinguished when the distribution ranges of species were considered. The vertical splitting of semi-compound rays in Lithocarpus with the formation of a vertical wedge of fusiform cells differed from the ray development so far reported in Fagaceae or other taxa that have broad rays, and occurred only in the subgenus Pasania.