| Gnetaceae is one of the most advanced families in the gymnosperms, and its morphological characteristics similar to that of angiosperms. It contains only one genus: Gnetum. The plants of Gnetum distributed in tropical and subtropical areas of Asia, Africa and South America. It comprises about 40 species, of which 9 are distributed in China. A majority of species in Gnetum have relatively limited distribution ranges and have relatively few wild resources. Though some species (e.g. Gnetum montanum) are somewhat widely distributed, the populations of these species are also in danger under over exploitation of human beings. Both G. montanum and G. leptostachyum are on red list of protection species internationally, but no assessment on more restricted species G. parvifolium.Gnetum parvifolium distributes mainly in Fujian, Guangdong, Guangxi, Guizhou, Hainan, Jiangxi and Hunan of China. It grows in forests of arid land or humid valley below the altitude of 1000m. It is common in Fujian and Guangdong, with Nanping of Fujian (N26.6°) as the north boundary of this species and also the family. G. parvifolium had been on the red list of protection species in Jiangxi and also been evaluated as 'Near Threatened (NT) nearly met Vulnerable (VU)' by China Species Red List published in 2004. However, there were no studies on G. parvifolium community yet. Under this background, we selected Fujian for investigating the wild resource of G. parvifolium population. 16 counties were investigated at 5 travels. Guided by quadrat method, we studied the characteristics of 10 Gnetum parvifolium communities simultaneously. The result shows that:(1) The community of G. parvifolium in Fujian is mainly distributed in the south of Nanping and Luoyuan (near N26.6°) and in the east of Longyan and Sanming. The distribution range was decreased in comparison with that of the previous records.(2) The populations of G. parvifolium show a growing tendency in Fujian. However, under influence of internal population characteristics and human disturbance, the numbers of adult plants are far fewer than that of young plants, which would lead to an unstable population development.(3) There are 300 species of vascular plants in G. parvifolium community plots, belonging to 172 genera and 88 families. Species of dicotyledon are dominant in the plot, while species of gymnosperm are scarce. The relative large families (with 10 or more species) include Lauraceae, Theaceae, Rubiaceae, Fagaceae, Myrsinaceae and Rosaceae in G. parvifolium community. The percent of genera with only 1 species or 2～5 species is 96.51% in total.(4) The phytogeographic components of G. parvifolium community in Fujian are complex, which contain 9 areal types of families and 12 areal types of genera. 79.01% of families and 76.25% of genera are tropical elements, and the majorities are pantropical ones especially. The temperate components of families and genera occupied fairly low percentage, accounting for 21.90% and 23.75% respectively. The families or genera of East Asia or Endemic to China are scarce in the community. The floristic origin of G. parvifolium community is ancient. The community also has some rare or endangered plant.(5) The phanerophytes occupies the dominant position in G. parvifolium community in Fujian, which reflects a muggy community habitat. Compare with life-forms of other communities, the result revealed that G. parvifolium community has transitional characteristic of middle subtropical evergreen broad-leaved forest to lower subtropical monsoon evergreen broad-leaved forest. The features of the leaves are mainly simple, small and medium, herbaceous and coriaceous.(6) The vertical structure of G. parvifolium community is relatively complicated which can be divided into tree layer, shrub layer and herb layer obviously. As a whole, except Daqing Mountain plot, the tree layer can be divided into 2~3 sub-layers. Dominant species in tree layers mainly included Phyllostachys edulis, Schefflera heptaphylla, Rhododendron rivulare, Castanopsis fissa, C. fargesii, C. eyrei, Machilus velutina, Liquidambar formosana and so on. The shrub layers have the most species diversity among the three layers, with Blastus cochinchinensis, Psychotria rubra, Maesa japonica, Trachelospermum jasminoides, Millettia ssp., Fissistigma oldhamii and so on as the dominant species. The species in herb layer mainly belonged to Pteridophyta, which include Dicranopteris dichotoma, Adiantum flabellulatum, Selaginella doederleinii, Woodwardia japonica, Dryopteris ssp., etc. G. parvifolium can be found in shrub layers or tree layers. It was the dominant species in some plots, such as in Lingshi Mountain (in Fuqing), Jiuli Lake (in Xianyou), Tianzhu Mountain (in Changtai) and Zijin Mountain (in Longyan), respectively.(7) In respect of vegetation type, species diversity is the highest in lower subtropical evergreen broad-leaved forest and is the lowest in bamboo grove in tree layer, whereas it's the highest in bamboo grove and the lowest in lower subtropical evergreen broad-leaved forest in shrub and herb layer.(8) Among three layers of G. parvifolium community in Fujian, the species diversity is the highest in shrub layer and the lowest in herb layer. It is in accordance with the common phenomena of species diversity in subtropical forest ecosystem. Comparing the species diversities to other forest communities, it shows that the community of G. parvifolium bears relatively high species diversity.
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