| Abstract: | Pollen morphology of 16 Chinese species representing 7 genera in the tribe Cynoglosseaeof Boraginoideae(Boraginaceae) was examined under LM and SEM, and 5 species under TEM. Pollen grains are cocoon-shaped, rarely subprolate, prolate or ovoid, very small, 7～ 15.7μm× 3.5 ~13.9 μm in size, P/E = 1.6～2.02; 3-colporate apertures alternate with 3-pseudocolpi, with equatorial endocingulus except those in Bothriospermum; exine surface is usually smooth, with or withoutperforations in two poles, rarely with tuberculate ornamentation; exine is rather thin and includesectexine and endexine, while ectexine consists of imperforate tectum, columellae and foot-layer.The tribe Cynoglosseae has many common characters of pollen grains, but there are some differencesamong genera. A key to the genera is given based on pollen morphology. Bothriospermum, withoutendocingulus, may be a primitive genus in this tribe, and its pollen morphology is more similar tothat of Eritrichieae than to Cynoglosseae, thus it seems more reasonable to put it into Eritrichieae.Solenanthus may be the most advanced genus in the tribe Cynoglosseae for its pollen grains of sub-isopolar and ovoid shape. |
