Systematic wood anatomy of the subfamily Acalyphoideae s.l. (Euphorbiaceae) from India, with remarks on synonymy

Abstract

The present paper deals with the wood microstructure of 18 species belonging to 8 genera classified in four tribes of the subfamily Acalyphoideae s.l. (Euphorbiaceae). The study mainly focuses on the systematic implications of wood anatomy to the subfamily, but also ecological and evolutionary aspects are evaluated. The wood microstructure of the subfamily was found to be considerably homogeneous except for that of the tribe Chaetocarpeae. The results support the segregation of Hancea from Mallotus and merging of Trewia into Mallotus. It is further suggested to include Mallotus nudiflorus in Mallotus sect. Philippinensis instead of Mallotus sect. Rottleropsis. Wood anatomical data turned out to solve the synonymic problem of Mallotus albus, Mallotus macrostachyus and Mallotus tetracoccus as well as Macaranga denticulata and Macaranga pustulata as the results indicate that these species are all distinct. The sectional circumscriptions of Macaranga and Mallotus are evaluated based on wood anatomical data. Radial laticifers are reported for the first time in Macaranga indica. A species identification key to Indian species of Acalyphoideae based on wood anatomical characteristics is provided. Table 1. List of specimens and studied species with their accession numbers, collector names and localities of the subfamily Acalyphoideae.