重庆地区石灰岩植被区系组成分析

重庆地区石灰岩植物组成简单,区系成分复杂,已经鉴定定名的维管植物有97科244属338种.其中蕨类植物14科17属24种,裸子植物2科2属2种,被子植物79科225属312种.从生长型看,乔木49种,灌木92种.藤本45种,草本152种.区系分区为泛北极植物区,中国—日本森林植物亚区,华北植物地区.属分布区类型热带成分42.62%,温带成分42.62%,地中海成分0.82%,中国特有成分1.23%;全世界分布的有24属.植被以草本占优势,木本多落叶成分,纸质叶最多,小型叶占极大比例,有肉质叶;喜钙植物丰富;植株多具针刺,鳞片;次生性明显.森林群落少,灌草丛多,这与石灰岩地区的干旱和土壤含钙丰富,以及土层瘠薄,有机质含量少是相适应的.

THE FLORISTIC ANALYSIS OF PLANTS IN THE CALCAREOUS REGION OF CHONGQING

Though the composition of the plant species is simple, the floristic elements are complicatec in the calcareous region of Chongqing. According to A. Engler' s system, the identified vascular plants here belong to 338 species of 244 genera of 97 families. Thsse plants include 24 species of 17 genera of 14 families pteridophtes, and other 312 species of 225 genera of 79 families angiosperms. As to the growth type, there are 49 species of trees, 92 species of shrubs, 45 species of liana and another 152 species of herbs. The flora here belong to the Central China region of Sino-Japan Forest subkin-dom of the Holarctic Kindom. On the distribution patterns of genera there are 104 genera tropical, 104 genera of teinperate, 24 genera of cosmopolitan!, 2 genera of Mediterranean and 3 genera of China-endemic distribution. For the vegetation, the herb is dominant. Most of the leaves are chartaceous and microphylls and many plants have spins and scales. The secondary characteristics of the vegetation is very obvious. The forest communities here are rare, while the shrub and herb communities are common, which is firmly connected with the environmental conditions in the region, i. e. lack of water, richness of Ca2+, poor soil and shortage of organic matters.