Seed Micromorphological Characteristics of Eurya and Their Systematic Implications

The seed micromorphology of 36 taxa (including 35 species and one variety) from Eurya was investigated using scanning electron microscopy (SEM).Micromorphological cha-racters, including seed relative size (length譿idth, RS) and ornamentation of the seed-coat were investigated.Three seed sizes were recognized: (i) mini type (RS<1.0), (ii) middle type (1.03.0).The relative sizes of the smallest seeds were less than 0.5 mm² and the largest seeds were more than 10 mm².Two types of ornamentation of the seed-coat were described: (i) reticulate grain and (ii) negative net grain.The orientation, shape and depth of lumina, and the characters of muri varied among different species, which could be used to identify species.The systematic and phylogenetic implications of seed size and seed-coat micromorphology in the genus Eurya are discussed based on our results.The evolutionary route of seed-coat ornamentation is also conjectured.Our study showed that seed micromorphological characters provided useful data for studying the evolution of Eurya and formulating the phylogenetic positions of several key species in this genus.