Studies On The Flora And Phytogeography Of Longgang National Nature Reserve Of Guangxi, China

The floristic compositions, characteristics and endemism in Longgang National Nature Reserve were comprehensively studied and the rare and endangered plants were evaluated and summarized on the base of literatures, field investigation, and specimen collection and identification. The main results are as follows:1. There are 1725 vascular plants species (including subspecies, varieties and forms) belonging to 799 genera in 183 families in Longgang National Nature Reserve, of which 64 species of cultivated plants belong to 59 genera in 37 families,22 species of naturalized plants belong to 21 genera in 16 families and 1639 species of wild vascular plants belong to 753 genera in 175 families.2. There are 146 species of pteridophytes belonging to 49 genera in 29 families were recorded in Longgang National Nature Reserve. The dominant families are Polypodiaceae, Thelypteridaceae, Pteridaceae, Aspleniaceae, Tectariaceae, Selaginellaceae, adding up to 92 species and covering 63.01% of the total pteridophytes in Longgang National Nature Reserve; The dominant genera are Pteris, Cyclosorus, Selaginella, Pyrrosia, Asplenium, Adiantum, Colysis, Microlepia, Microsorum, adding up to 80 species and covering 54.79% of the total pteridophytes in Longgang National Nature Reserve. The tropical and subtropical endemic elements are dominant for the pteridophytes in the region.3. The wild gymnosperms are scarce and only 8 species belong to 5 genera in 4 families were found in the region, holding a low proportion of the total wild vascular plants in Longgang National Nature Reserve,0.49% of the total species,0.66% of the total genera and 2.29% of the total families.4. There are 1485 species of angiosperm belonging to 699 genera in 142 families were recorded in Longgang National Nature Reserve. The dominant angiosperm families are Euphorbiaceae, Rubiaceae, Fabaceae, Gramineae, Asteraceae, Orchidaceae, Moraceae, Lauraceae. Urticaceae, Acanthaceae, Liliaceae, Asclepiadaceae, Rutaceae, Rhamnaceae. Vitaceae, Gesneriaceae, Verbenaceae, Annonaceae,Apocynaceae, Rosaceae, Cucurbitaceae, Caesalpiniaceae, Oleaceae and Labiatae, covering 56.11% and 59.47% of the total angiosperm genera and species respectively found in Longgang National Nature Reserve. The dominant angiosperm genera are Ficus, Jasminum, Begonia, Justicia, Elatostema, Clematis, Rubus, Chirita, Capparis, Zanthoxylum, Mallotus, Ophiopogon, Ardisia, Tetrastigma, Carex and Litsea. The tropical and subtropical endemic elements are also dominant in the angiosperm flora in the region.5. The tropical and subtropical endemic elements, especially the Pantropical ones, are dominant in the flora in Longgang National Nature Reserve. The pteridophyte families in the region are all tropical or subtropical endemic elements except the Cosmopolitan families. The tropical and subtropical elements cover a high generic and species proportion of 73.47% and 52.05% respectively for pteridophytes, which are obviously higher than temperate elements with a ratio of 9.00:1 and 2.92:1 respectively. For the spermatophyte, the tropical and subtropical elements cover 73.47% and 52.05% of the total found families and genera, respectively, which are also obviously higher than the temperate elements with a ratio of 5.44:1 and 6.10:1 respectively.6. Majorities of the recorded families and genera in Longgang National Nature Reserve are monotypic or oligotypic, namely having solitary or few species. There are 20 and 39 monotypic or oligotypic families and genera (less than 4 species) with a proportion of 68.97% and 79.59% of the totals, respectively, for the pteridophytes. There are 102 and 662 monotypic or oligotypic angiosperm families (less than 10 species) and genera (less than 5 species) with a proportion of 69.86% and 94.03%, respectively.7. Through field investigations, eight new species (Pteris pseudogrevilleana, Cyclosorus longgangensis, Chirita ningmingensis, Chirita sinovietnamica, Lagarosolen longgangensis, Calanthe longgangensis, Ophiopogon rupestris, Begonia longgangensis) were discovered and identified; one newly recorded species (Phaius tonkinensis) for China, ten newly recorded species and one newly recorded genus (Pycnarrhena) for Guangxi were found in Longgang National Nature Reserve.8. Numerous East Asia, China or Guangxi endemic taxonomic groups were found in Longgang National Nature Reserve:Actinidiaceae is endemic to East Asia; 8 spermatophyte genera (Heteroplexis, Pseudochirita, Pteroceltis, Koelreuteria, Tapiscia, Lagarosolen, Petrocodon, Indocalamus) are endemic to China; 41 pteridophyte species belonging to 23 genera in 14 families are endemic to China, covering 28.08%,46.94% and 48.28% of the total pteridophyte species, genera and families found in Longgang National Nature Reserve; 91 spermatophyte species are endemic to Guangxi, covering 6.10% of the spermatophytes found in Longgang National Nature Reserve and 10.34% of the total species which endemic to Guangxi. There are also lots of limestone endemic taxa, showing distinct limestone floral characteristics for Longgang National Nature Reserve. 9. There are 31 rare and endangered species (including 5 pteridophyte species,3 gymnosperm species and 23 angiosperm species) belonging to 27 genera in 24 families in Longgang National Nature Reserve, of which 21 species belong to the List of Rare and Endangered Plants Under State Protection(Vol.1,1987), and 19 species belong to the List of Wild Plants Under State Key Protection (1999,3 species under first class state protection). The 31 rare and endangered species and some other vascular plants has been assessed under the criteria of the IUCN, and 171 species are suggested to be listed in the Plants List of Under State Protection.