Anther structure and pollen ontogeny of Hosta Tratt. and its systematic significance

Anther structure and pollen ontogeny of six species of Hosta Tratt. was studied to provide additional data for its classification. Microscopic observation found that their male gametogenesis has the following structural characteristics: (1) the four microsporangia are linearly arranged on introrse side of anther connective tissue; (2) mature anther wall is composed of an epidermis, endothecium, middle layer(s), and tapetum; (3) microsporogenesis is successive; (4) mature pollen grains are three-celled at anthesis, with a vegetative cell filled with large amounts of starch grains; (5) pollen ontogeny is obviously asynchronous; (6) each tepal has about 9?C13 vascular traces in cross-section view. The above observations suggest that genus H. Tratt. should be classified as family Hostaceae, in agreement with Dahlgren and Clifford (1982), Takhtajan (1997), and Wu et?al. (2003).