Taxonomy Study On Genus Spiraea Linn. In China

Based on specimens of genus Spiraea L. collected in China, the classification and stysterm evolution of Spiraea were studied, concentrating on the micromorphology of seeds and leaf epidermis. Method of numerical taxonomy was also applied in this paper. The results are listed as follows:(1)Seeds of Spiraea are linear or narrowly elliptic in shape, glossy and striated on the surface and reddish brown to puce in color. Seed-coat sculptures have four types: reticulate, double-reticulate, areolate and chainlike-reticulate. The L/W ratios of seeds supported the traditional taxonomic division on the sectional and serial level in this genus.(2)The shapes of upper and lower epidermal cells of most Spiraea species are irregular. Except for S.elegans and S.aquilegifolia, the stoma of the rest species in this genus distribute in the lower epidermal cells. Stomatal shapes are oval, long elliptic or suborbicular. Stomatal apparatuses are classified into three kinds: anomocytic, cyclocytic and atypical actinocytic. Outer stomatal rims of most species are unilaminar. Most specimens have trichome, which is unicellular, nonglandular and branchless. Cuticular ornamentation of leaf epidermis is various.(3)Traits clutering analysis results showed that the distribution of 41 traits choosen herein is sparse and the correlation between traits is not strong. It is clear that the variation of morphological traits, to some extent, is independent in the process of evolution in the genus Spiraea.In conclusion, the results of morphology of seeds and leaf epidermis, plus the numerical taxonomic analyses, can offer reference for specific identification, and provide data to systematic evolution studies on Spiraea.