A Systematic Study Of The Genus Nannoglottis Maxim.(Compositae)

Nanno glottis Maxim., a genus mainly distributed on the Qinghai- Xizang(Tibetan) Plateau, is one of the 21 problematic genera of Compositae. According to the delimitation by Ling&Y.L.Chen, it comprises members of 5 genera as follows :Nannoglottis,Stereosantus,Vierhapperia,Senecio and Doronicum. It has been placed in Inuleae by Maximovicz and Franchet, in Senecioneae by Hoffmann and Ling &Y.L.Chen, in Astereae by Handelazzetti, Jeffery &Y.L.Chen ,Zhang& Bremer and Nesom. Some important characters of Nannoglottis, such as ligule colour, chromosome number et al. are rather badly known. Because of less field work and inaccessibility to most type specimens, the revision of this genus by Ling&YL.Chen is not satisfying. In this dissertation, evidence from gross-morphology, micromorphology, anatomy , palynology, cytology, ecology and ITS data is produced for its taxonomy, its tribe and subtribe position, and a new infrageneric system is presented. 1 .Gross-morphology On the basis of examination of a large number of herbarium specimens (including most types) and extensive observation of field populations, the variation pattern of major gross-morphological characters was analyzed and their significance for a better delimitation of the species was evaluated . Nine species were recognized as follows:N. carpesioides Maxim., N. delavayi(Franch.)Ling et Y.L.Chen, N gynura (C.Winkl.) Ling et YL.Chen, N. hieraczphylla (Hand-Mzt.) Ling et YL.Chen, N. hookeri (C.B.Clarke ex Hook.f.) Kitam., N. latisquama Ling et Y.L.Chen, N.macrocarpa Ling etY.L.Chen, N. ravida (C. Winkl.) YL.Chen, N.yuennanensis (Hand.桵zt.)Hand.? Mzt.,N.souliei (Franch.) Ling et Y.L.Chen was reduced to N gynura(C. Winkl.) Ling et Y.L.Chen. 2 .Micromorpholoy The style branch shape, anther apex sterile apendage, anther base, style base, nectary, filament collar and endothecial cell pattern of 9 species of Nannoglottis and 2 representatives of Astereae were investigated under light microscope. Except the - lv - style base, other micromorphological characters are constant within Nanno glottis. The acute shape of the style branch of disc florets indicates a connection betweeen Nanno glottis and Astereae, while the polarized endothecial pattern indicates a connection betweeen Nannoglottis and the Inuleae s.l.. 3 .Anatomy Leaf epidermis of 8 species of Nanno glottis were investigated under both light microscope and scanning electron microscope. The stomata is constant within the genus, belonging to the anomocytic type. The shape of epidermis cell of N. ravida is polygonal , while the other species are irregular. The thickness of cuticle of N. ravida is also quite different from the other species. 4. Ligules and style branch under SEM Epidermis of ligules of 8 species of Nanno glottis and 7 representatives of Astereae was investigated under SEM. The adaxial epidermis of Nannoglottis is tabular celled and characterized by thickening along the median plane of cell. The Asteroid epidermis is typical of all Nanno glottis species studied. But the epidermis cells of Nanno glottis are mainly longitudinally rugose or striate, quite different from the constantly transversely rugose or striate cuticle patterns of Astereae. Adaxial surfaces of the style branch of the disc florets of 8 species of Nanno glottis and 8 representatives were investigated under SEM. Sty...