Studies On Systematics Of The Genus Hedysarum L. From China

The genus Hedysarum, belonging to the tribe Hedysarean of subfamily Papilionodeae in Leguminosae, comprises more than 150 species distributed in Europe, Asia, North America and North Africa of temperate to boreal regions of the North Hemisphere. The genus are known about 42 species, 10 varieties and 1 subspecies according to the record of Flora Reipublicae Popularis Sinicae in vol 42, No. 2, which were classified into 4 Section, namely, Sect. Obscura, Sect. Multicaulia, Sect. Subacaulia and Sect. Fruticosa. They were distributed mainly in inland arid and cold areas as well as Himalaya alpine regions in China. Hedysarum possesses important value in economy, most species for foraging, some for medicinal value, less for decorative plants, still some for honey-bee plants, in desert and semidesert regions, semishrub species play important roles in sand-shifting control.Studies on the genus began to early Linnaeus times. Subsequently, Fedtschenko, Choi, Ohashi, Xu LR and Zhao YZ et al. contributed to Hedysarum, and made admirable achievements. Even so, there are still various problems needed to further research. According to field investigation, identification and experimental conditions, we have put emphasis mainly on some problems as follows:1. After most species of the genus Heysarum were examined and supplied on classical taxonomic literatures, herbarium works and field investigation from literature citation, geographical distribution, identification features, ecological characteristic, chromosome number, type specimen and herbarium, 44 species, 13 varieties, 1 subspecies and 1 forms were recognized in China at present. These species occured mainly in grassland, alpine and desert regions in Xinjiang, Gansu, Ningxia, Neimonggu, Xizang, Shaanxi, Yunnan, Northwest of Sichuan and North of Hebei province, few species of which extended up to the West of Northeast and Mt. Zhu in Hubei province.2. Pollen morphology of 21 taxa of the genus Hedysarum, distributed in China, were studied with light and scanning electron microscopy. The pollen is 3-colpate in common, 3-colporoidate in rare, medium or large in size, with reticulate ornamentation. Pollen grain prolate, triangular-obtuse in polar view, rectangular-obtuse to elliptic in equatorial view, Polar diameter 15.6～30.25μm, equatorial diameter 9.0～19.5μm, P:E=1.28～1.85, dimensions P ×E=(18.03μm～27.55μm)22.16μm×14.32μm (12.13μm～18.76μm). Ornamentation...