Embryological studies on Abelia tyaihyoni Nakai (Caprifoliaceae)

摘要: Abstract Abelia tyaihyoni is a Korean endemic species and also designated as an endangered taxon in the IUCN Red List. We present comprehensive embryology of A. tyaihyoni, comparing it with previously available information on Caprifoliaceae related families, identifying possible evolutionary trends. Overall, comparisons showed that similar to other genera many embryological features, including tetrasporangiate anther, anther wall, dicotyledonous wall formation, fibrous endothecium, simultaneous cytokinesis, tetrahedral tetrads, three-celled pollen grains. In addition, share anatropous, unitegmic, tenuinucellate ovules, ephemeral antipodals, cellular-type endosperm caprifoliaceous genera. Some such amoeboid tapetum several nuclei forming polyploid mass, bisporic Allium-type embryo sac, obturator, bilayered endocarp, compressed exotesta, are here described for first time this genus. The results confirm shares some significant features Caprifoliaceae. Although previous studies lack convincing explanations, our comparative approach demonstrates apomorphies presence two sterile carpels, single-seeded fruit, sclerified exotesta.