Abstract:

Nutlet morphology and micromorphology of 27 species with four varieties of Carex sect. Paniceae were observed under scanning electron microscopy（SEM）. The results showed that：（1）The nutlet shape of all samples（beak excluded） were obovoid trigonous， with the length ranged from 1.53-3.59 mm. The nutlet length between different populations of the same species revealed stability and no significant difference exist by statistical analysis. （2）The epidermal cells were five to seven gonal， rarely four or eight， which was various within the different individuals of C. rouyana. The anticlinal wall was straight or microwave， and silica platform was flat， occasionally concave or slightly convex， with solitary central silica body but without satellite body. Whereas each epidermal cell of C. filipes var. kuzakaiensis and C. filipes var. tremula occasionally had two central silica bodies. （3）Based on the shape of epidermal cells， numbers of central silica platform， some species were distinguished from similar species， such as C. baimaensis and C. filipes， and it was also valuable to distinguish the varieties of C. filipes， ie. var. kuzakaiensis， var. oligostachys and var. tremula. （4）Sections Paniceae s.s. and Laxiflorae had a high consistency in the morphology and micromorphology of nutlets. It indicated that the morphology and micromorphology of nutlets were of great importance of taxonomic significance.

Key words: Carex, sect.Paniceae, nutlet, micromorphology, taxonomic significance