|其他摘要||In this thesis, the macromorphological and micromorphological characters of Lepiota from China and molecular phylogeny based on ITS, LSU, IGS and mtSSU sequences of the genus were studied. The infrageneric system and phylogeny within the genus were discussed. The relationships of morphological and phylogenetic species in the complex Leucoagaricus viriditinctus, previously placed in Lepiota, were elucidated based on ITS, LSU, IGS, mtSSU, EF1a and BIP sequences data. Genetic diversity and biogeography of L. cristata were inferred from ITS，IGS and mtSSU sequences. The main results are summarized as follows:
1. Taxonomy and systematics
Specimens (including some types) of Lepiota (abbreviated as L. here) and Leucoagaricus (abbreviated as La. here) from China, Sri Lanka, Europe and North America were examined. As a result, thirty-six species of Lepiota and six species of Leucoagaricus were identified, of which sixteen species and two varieties are new to science, namely, L. ochraceosquamea J. F. Liang & Zhu L. Yang, L. ampliocystidia J. F. Liang & Zhu L. Yang, L. submagnispora J. F. Liang & Zhu L. Yang, L. fusco-brunnea J. F. Liang & Zhu L. Yang, L. contractispora J. F. Liang & Zhu L. Yang, L. subcastanea J. F. Liang & Zhu L. Yang, L. pseudocristata H. C. Wang ex J F. Liang & Zhu L. Yang, L. pallidiochracea J. F. Liang & Zhu L. Yang, L. megaspora J. F. Liang & Zhu L. Yang, L. angusticystidia J. F. Liang & Zhu L. Yang, L. rubro-brunnea H. C. Wang ex J F. Liang & Zhu L. Yang, L. brunneosquamula J. F. Liang & Zhu L. Yang, L. stillispora J. F. Liang & Zhu L. Yang, La. viridianus J. F. Liang & Zhu L. Yang, La. azurescens J. F. Liang & Zhu L. Yang, La. brunneocanus J. F. Liang & Zhu L. Yang, L. clypeolaria var. nigrosquamosa H. C. Wang ex J F. Liang & Zhu L. Yang and L. subcastanea var. bispora J. F. Liang & Zhu L. Yang. Five species, viz. L. aspericeps Murrill, L. kuehneriana Locq., L. brunneolilacea Bon & Boiffard, L. jacobi Vellinga & Knudsen and La. tener (P.D. Orton) Bon, are new to China. Two new combinations, L. cristata var. macrospora (Zhu L. Yang) J. F. Liang & Zhu L. Yang and La. viriditinctus (Berk. & Broome) J. F. Liang & Zhu L. Yang, are proposed.
Based on morphological and anatomical characters, Lepiota was divided into five sections, namely, sect. Lepiota, sect. Stenosporae (Lange) Kühner, sect. Ovisporae (Lange) Kühner, sect. Cristatae (Kühner ex Wass.) Bon and sect. Echinatae Fayod. A key to the sections of the genus and keys to the species studied in each section were provided. Additionally, a key to a few species in an allied genus Leucoagaricus was provided.
2. Molecular phylogeny
In virtue of some analytic methods such as Most Parsimony analysis, Bayesian analysis, T-PTP (the topology-dependent permutation tail probability) test, PH (the partition homogeneity) test and Genetic distances analysis (HKY85), data sets of ITS, LSU, IGS and mtSSU sequences of Lepiota were analyzed. It was revealed that all five sections based on morphology are polyphyletic, thus the existing infrageneric morphology-based system is imperfect. The evolutiona pileus and basidiospores were speculated. The evolutional approach of pileus might be from trichoderm to hymeniform to inflated elements in chains, while the evolution of basidiospores might be from penguin-shaped or fusiform forms to ellipsoid to triangular or subcylindrical ones.
3. Relationships of morphological and phylogenetic specie
Relationships of morphological and phylogenetic species in La. viriditinctus complex were inferred from ITS, LSU, IGS, mtSSU, EF1a and BIP sequences data. The results showed that La. viriditinctus complex consist of five phylogenetic species, and thus, a morphological species might cover one or more phylogenetic species in lepiotaceous fungi. Evolutional rates of ITS, LSU, IGS, mtSSU, EF1a and BIP genes in the genus were compared and founded that the rates of these genes are faster and faster from the first to the last, namely, LSU → mtSSU → ITS →（EF1a, BIP）→ IGS.
4. Population genetics and biogeography of L. cristata
Genetic diversity and biogeography of L. cristata were inferred from ITS, IGS and mtSSU sequences. It was revealed that there was sufficient evidence supporting long-distance gene flows among geographic populations and such gene flows are quite common. The gene flow could contribute to the lack of an overall geographic pattern of genetic variation in L. cristata populations. The white basidiospores might be dispersed for long-distance. It was contrary to the former result that white basidiospores were not suitable for long distance dispersal. Population genetics studies revealed a new cryptic species, L. pseudocristata, and a new combination, Lepiota cristata var. macrospora.|