摘要
通过对贺兰山禾本科植物的采集调查和分析研究，发现本区有野生禾本科植物４１属、１１２种、６变种。从垂直分布来看，随着海拔由低到高的变化，种类的分布和数量都有明显的改变，其中在山地荒漠带（海拔１４００－１６００米）有３３种左右。占本区禾草总数的２８％，在山地疏林草原带（海拔１６００－２０００米）有３０种左右，占２５．４％；在山地针叶林带（海拔２０００－３０００米）约有３８种，占３２．２％；而在山地灌丛草甸带（海拔３１００－３５５６米）仅有８种左右，占６．８％。在水平分布方面，本区南部几乎包含了整个山体分布的所有禾草，而在北部分布的种类则不超过４０种。从属的分布类型来看，本区汇集了８个分布类型，其中温带分布类型有２７属，占全部禾草属数的６５．７％；热带分布类型有１０属，占２４．４％。另外本区系的禾本科植物还具有如下几个特点：（１）种类丰富，种属比值居上，是贺兰山种子植物区系中的第一大科；（２）种的地理成分混杂；（３）分布广泛，建群种和优势种较多。
By means of collecting,investigating and studying of Gramineae in Helan Mountain,we discover it contains 41 genera,112 species and 6 varieties.In vertical direction,there are 4 distribution zones.In the mountain desert zone(1400-1600m alt),there are about 33 species,which are 28 percent of whole grasses in the area.In mountain open woodland-steppe zone(1600-2000m alt.),there are 30 species,and the percentage is 25.4,In the mountain coniferous forest zone(2000-3100m alt.),there are about 38 species,whose percentage is 32.2.Only 8 species (about 6.8%) occur in the subalipe scrub and meadow zone(3100-3556m alt.),In horizontal direction,almost all species of Gramineae in the Helan Mountain(more than 100 species)appear in the southern part of this area.In the northem part,however,there are less than 40 species.As for the distrbution-type of genera,the Mt.Helan consists of 8 distribution-typies,among which the temperate typies(27 genera) have a percentage of 65.7% of total genera and the tropical typies (10 genera),24.4%.In addition,the floristic characteristics of the family Gramineae in this area are as follows:(1)Species are rich,and the ratio of species and gemus is high.(2)The geographical elements are mixed.(3)The distribution is widespread and the community species or dominant species are more than other families. \ \
出处
《干旱区资源与环境》
CSCD
1999年第2期17-24,共8页
Journal of Arid Land Resources and Environment
关键词
贺兰山
禾本科
生态地理分布
区系
特征
植物
Helan Mountain, Gramineae, ecogeographical distuibution, flora.
