作 者 ：WU Peng-Cheng, JIA Yu, WANG Mei-Zhi
期 刊 ：植物分类学报 2001年 6期
Keywords:Floristic relationship, China, North America,
Abstract:
In this paper, we analysed in detail both hepatic flora and moss flora of China and North
America to have a better understanding of the bryological relationships between these two continents.
The results show that the similarity coefficient of the bryophytes between China and North America is
very high (up to 88.03%) at the family level, but very low (only 18.88%) at the species level.
Although the separation of the two ancient continents started in the late Cretaceous, the bryophytes
between China and North America with respect to the composition of families and genera are still
close. Nevertheless both continents have had their own endemic genera of liverworts and mosses.
There are five East Asiatic endemic genera of liverworts and 22 East Asiatic endemic genera of moss-
es in China, while there are four liverwort genera and five moss genera endemic to North America.
It is noteworthy that the bryological relationships between eastern North America and China show a
quite different pattern from those between western North America and China with respect to the fami-
lies, genera and species. The sexuality of plants and the size of spores of liverworts and mosses may
not be the main factors that have influenced the distribution of the bryophytes in China and North
America, although they are of some importance for the distribution of bryophytes. Various informa-
tion concerning the bryological relationships between China and North America (including the simi-
larity coefficients of the bryophytes of China and North America at different levels, their endemic
genera, the sibling species of the two continents, the geological history and physical geograhical
conditions of China and North America, and the biological characters of bryophytes) has been anal-
ysed. It is considered that there exist close bryological relationships between China and North Amer-
ica, although in these two separated continents some local and endemic genera had been formed after
the Cretaceous. Both bryofloras have been influenced by those of their neighbouring regions, and the
Bering Strait may not be a natural barrier to prevent the bryological exchange between China and
North America. In summary, the present relationships of the bryofloras between China and North
America have been formed not under the influence of one simple facter or event but under a compre-
hensive influence of many factors or events during the geological history.