Pollen morphology of 16 Chinese species representing 7 genera in the tribe Cynoglosseae
of Boraginoideae(Boraginaceae) was examined under LM and SEM, and 5 species under TEM. Pol-
len 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 equa-
torial endocingulus except those in Bothriospermum; exine surface is usually smooth, with or without
perforations in two poles, rarely with tuberculate ornamentation; exine is rather thin and includes
ectexine 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 differences
among genera. A key to the genera is given based on pollen morphology. Bothriospermum, without
endocingulus, may be a primitive genus in this tribe, and its pollen morphology is more similar to
that 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.
