Shandong Sedge Family Plant Micromorphology And Phylogenetic Analysis Based On Morphological Evidence

The family Cypereae is established on the type of Cyperus L. which is set up in Linnaeus (1753) book《Species Plantarum》by the Belgian botanist Dumortier in 1829. From the beginning of the establishment of this tribe, though different classification systems have put forward a wide range of views for the Cypereae taxonomic scope, there is still no mature scheme. The study of these classification systems on Cypereae is all limited to morphology, and traditional taxonomic methods are used to establish the system, i.e. the weighting approach is taken to some characters. There is still no micro-morphological study on Cypereae and there is no system set up on the character equality attitude. In the present study, we select Shandong Province as the study areas where 24 types of Cypereae plants distributed are studied in pericarp and bracts epidermis micromorphology. Based on studies of plant morphology and the conclusions of the above two, taking the numerical classification method, we study and examine the categories range of Cypereae in Shandong province. Hopefully, we can provide some constructive suggestions on the nationwide classification system of Cypereae. The results are as follows:1. Microphotographs of achenesAll Cypereae plants (24 species) distributed in Shandong province are examined and photographed under the scanning electron microscope of pericarp micromorphology. Three types of pericarp ornamentation are found here:reticular, tubercular, and reticular-tubercular ornamentation. The distribution of these three types of ornamentation is different from system established by traditional taxonomy. According to the study, Juncellus and Pycreus should be a separate genus respectively and not be incorporated into Cyperus; while Mariscus and Torulinium should be incorporated into Juncellus.2. Microphotographs of bractsThe bracts of Cypereae plants are examined and studied under the scanning electron microscope for the first time. No prickle hair and short cells are found on both the adaxial and the abaxial epidermis. The stomatal apparatus are paracytic, and the guard cells of stomata are dumbbell-shaped. The main differences lie in anticlinal walls trait of the long cell of bract epidermis; the presence or absence of silica particles in pulse area; the number of stomata in interpulse; the shape of the stomata accessory cells; and the number of layers of stomata outer ledge. Bract epidermis micromorphology features support the following conclusions:Juncellus should be a separate genus; there is a small distinction between Pycreus and Cyperus, Mariscus should be incorporated into Cyperus. However, the bracts of the ball-sequenced Torulinium are different from all the other genera of Cypereae. There is rich waxiness in adaxial epidermis while no stomatal apparatus in abaxial epidermis, which makes it difficult to determine its systematic position3. Morphological Evidence-based Phylogenetic AnalysisUsing the numerical taxonomy method of character equality, we select the 38 traits of 24 types of Cypereae plants in Shandong Province. The NTSYS-pc Version 2.10e software is used for data processing, and we get the Euclidean distance UPGMA cluster analysis diagram. According to this diagram we put forward a new proposal in the classification system of Cypereae in Shandong Province:Cypereae is divided into two subtribes named as Cyperinea and Juncellinea, with two genera named Mariscus and Cyperus in the former subtribe and one genus of Juncellus and in the latter. There are two subgenera named Cyperinea and Juncellinea in Cyperus. There is one error occurred in the whole proposal. That is, there appeared Mariscus in Cypereae subtribe, in which there are only two species:Mariscus radians and Cyperus exaltatus. This is due to the smaller distribution of both species in Shandong Province and the small number of specimens.