| The genus Cleistogenes Keng about 13 species, distributed in dry and semi-arid regions of the South Europe and northeast of China. In China, about 10 species and 1 subspecies(five endemic). The dominating identification standards of the genus are mostly characterized by some quantitative traits, e.g. the length of the glume, lemma and awn so fourth. Because of that, it causes dispute in the identification of species and subspecies of the genus. Some scholars put the genus in the Trib. Eragrostideae of Subfam. Eragrostoideae, but the specified morphological character of the genus is distinguished from the others of the Trib. Eragrostideae .As a result, the systematic status of the genus intrigues us to study.In this thesis, the systematic status and identification of the species and subspecies of the genus Cleistogenes have been documented by means of leaf abaxial epidermis, caryopsis morphology and molecular systematics, which provide new evidences for the puzzling problems awaiting to solve. The results are summarized as follows:1. Light microscopes are used to examine leaf epidermal features of the genus Cleistogenes and related genera of the family Poaceae. The results show that The genera Cleistogenes and Orinus are closely related according to the consistent character of the leaf abaxial epidermis. In both of the genera, the margins of the long-cells deeply sinuous or sinuous, the type of silica-bodies dumb-bell-shaped, solitary above the veins, one papilla per long cell, micro-hairs double-cells with the basal cells wedge-shaped and distal cells dome-shaped, short and strong, which are consistent with the basal characteristics of the Subfam. Eragrostoideae; It differentiates from the Subfam. Pooideae in the margins of the long-cells not sinuous or slightly sinuous, micro-hairs abscent; from the Subfam. Arundinoideae and Subfam. Panicoideae in the micro-hairs with the basal cells long-wedge-shaped and the distal cells tapering to a pointed apex, long and thin; from the Subfam. Oryzoideae in silica-bodies Oryza-shaped, many papillae on the same long cell, abundantly and dispersedly arranged, tapering to the apex, short and thin. Compared with the other tribles of the Subfam. Eragrostoideae, it is different from the Trib. Eragrostideae in the silica-bodies saddle-shaped.; from Trib. Chlorideae in the silica-bodies saddle-shaped and micro-hairs dome-shaped; from Trib. Sporobuleae in the silica-bodies in pairs, saddle-shaped and crescent-shaped, micro-hairs one-celled; from the Trib. Zoysieae in the silica-bodies in pairs, saddle-shaped and crescent-shaped. In morphological characters, the panicle of them are composed of a few racemes, the spikelets 1-several florets, lemmas 3-5-veins, apex bidenticulate, muronate or awned, blades ususally disarticulating from the sheaths because of the articulation, which are obviously distinguished from the other genera belonging to the Trib. Eragrostideae. As a result, the study proposes to support the foundation of the Trible Cleistogeae F. Z. Li & X. L. Lin.Combined the leaf abaxial epidermis with the morphology, it can be concluded that⑴Cleistogenes mucronata Keng ex P. C. Keng & L. Liu can be treated as the synonyms of C. festucacea Honda;⑵The results do not support C. chinensis Keng as the synonyms of C. hackelii (Honda) Honda,however it should be treated as a independent species;⑶Not support C. caespitosa Keng var. romosa F. Z. Li & C. K. Ni as a synonyms of C. hackelii (Honda) Honda, nor as a subspecies of C. caespitosa Keng,but should be treated as an independent species,namely C. ramosa (F. Z. Li & C. K. Ni) F. Z. Li & X. L. Lin com. nov.。⑷Strongly support the foundation of the new taxa, C. brevipalea F. Z. Li & X. L. Lin sp. nov.。Besides the leaf abaxial epidermis of the genus Eleusine is the same type with the Trib. Chlorideae, the silica-bodies solitary, saddle-shaped, micro-hairs dome-shaped, meanwhile they share the specified digitate inflorescence in the morphological characteristics, so the genus Eleusine ought to be transferred from the Trib. Eragrostideae to the Trib. Chlorideae. 2. Light anatomical microscopes are used to examine caryopsis features of the genus Cleistogenes and related genera of the family Poaceae. The results indicate that the genera Cleistogenes and Orinus are similar with each other, the same with the leaf abaxial epidermis, as a result of that, they are closedly related. Shape of caryopsis nearly triangular, caryopsis size medium, slightly convex on the ventral face, hilum elliptic or oblong, embryo proportion 2?5, style base persistent, laterally compressed. The above are consistent with the basal features of the Subfam. Eragrostoideae They are markly spicified compared with the Subfam. Arundinoideae in the hilum needle-shaped, dorsiventrally compressed; With the Subfam. Panicoideae in the caryopsis size large, half-spherical or over-half-spherical, the embryo proportion large, 1/2-3/4, dorsiventrally compressed; With Subfam. Pooideae in the shape of the caryopsis ensiform or converted-boat-like, caryopsis size large, hilum groove-like, the ventral face groove-like as well, the embyo proportion small, 1/6-1/3, style base absent; With the Subfam. Oryzoideae in the shape fish-like, hilum needle-shaped, the ventral face convex sharply, the embyo large, 3/4. Compared with the other tribles belonging to the Subfam. Eragrostoideae, the caryopsis of Trib. Eragrostideae is compressed-spherical or shuttle-shaped, the caryopsis size is small, 0.6-2.0mm; The Trib. Chlorideae triprismy-shaped, size small, 1.5-2.0mm, not noticeably compressed; The Trib. Sporobuleae tetraprismy-shaped, size small, 1-1.2mm; The Trib. Zoysieae fish-shaped, size small, 1.0-1.5mm.The characteristics of the caryopsis as the same support the foundation of the Trible Cleistogeae F. Z. Li & X. L. Lin, which belongs to the Subfam. Eragrostoideae. Except Cleistogenes songorica (Roshev.) Ohwi, the caryopsis size of which is small, the features of the others are highly consistent, so it is not suitable for the identifications of the species and subspecies in the genus.Moreover the caryopsis character of the genus Eleusine is consistent with that of the Trib. Chlorideae as well, combined with the result of the leaf abaxial epidermis , the genus should be transferred to the Trib. Chlorideae.3. The phylogenetic relationships between the genus Cleistogenes and related genera in the Subfam. Eragrostoideae and Subfam. Pooideae is discussed based on ITS sequences. The results show the nature monophyly of the genus Cleistogenes and support the foundation of the Trible Cleistogeae F. Z. Li & X. L. Lin, including the genera of Cleistogenes and Orinus, which are consistent with that from the observation of the characteristic of the leaf abaxial epidermis and the caryopsis feature. The results are consistent with what are obtained from the the leaf abaxial epidermis and the cayopsis feature, it can be concluded that⑴Cleistogenes mucronata Keng ex P. C. Keng & L. Liu can be treated as the synonyms of C. festucacea Honda;⑵C. hackelii var. nakaii (Keng) Ohwi should be transferred from C. hackelii (Honda) Honda to C. hancei Keng as a subspecies, namely C. hancei Keng var. nakaii (0hwi) F. Z. Li & L. X. Lin;⑶The results do not support C. chinensis Keng as the synonyms of C. hackelii (Honda) Honda, however it should be treated as an independent species;⑷Strongly support the foundation of the new taxa, namely C. brevipalea C. brevipalea F. Z. Li & X. L. Lin. The two species from the genus Eleusine appear in the same clade with the Trib. Chlorideae with a strong support. So the genus Eleusine ought to be transferrde from the Trib. Eragrostideae to the Trib. Chlorideae.
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