SYSTEMATIC VALUE OF THE ABAXIAL LEAF-BLADE EPIDERMIS IN AMERICAN SPECIES OF THE GENUS TRISETUM PERS. (POACEAE: POOIDEAE: AVENINAE)

Abstract

The abaxial leaf epidermis of 29 species and 3 varieties of Trisetum s.s. was studied. In addition, Deschampsia brasiliensis (Louis-Marie) Valencia (= Trisetum brasiliense Louis-Marie), Helictotrichon bulbosum (Hitchc.) Parodi (= T. bulbosum Hitchc.) and Peyritschia deyeuxioides (Kunth) Finot (= T. deyeuxioides Kunth), were included. Observations of the adaxial epidermis of some South American species were made with scanning electron microscope (SEM). Cluster analysis (UPGMA) and principal component analysis (PCA) were applied to a basic data matrix (35 OTUs x 17 characters of abaxial epidermis). Four groups of species were recognized: 1. Deschampsia brasiliensis. 2. Helictotrichon bulbosum. 3. Subg. Deschampsioideum (Louis-Marie) Finot (T. durangense Finot & P.M.Peterson, T. filifolium Scribn. ex Beal, T. palmeri Hitchc., T. tonduzii Hitchc., T. viride (Kunth) Kunth and T. virletii E.Fourn.), T. pringlei (Scribn. ex Beal) Hitchc. and T. rosei Scribn & Merr. (Subg. Trisetum). 4. Subg. Trisetum. Sections Trisetum and Trisaetera Asch. & Graebn., were not distinguished. On the basis of the studied characters the genera Trisetum and Peyritschia E.Fourn. were not recognized.