中国麻黄属的地理分布与演化

DISTRIBUTION AND EVOLUTION OF THE GENUS EPHEDRA IN CHIA

中国现有麻黄属（ＥｐｈｅｄｒａＬ．）植物１５种，２变种和１变型。这些种属于膜果麻黄组和麻黄组中的麻黄亚组，没有原始类型藤麻黄亚组的代表。我国除长江中下游及珠江流域的省区外，其他省区都有分布。麻黄花粉的化石───麻黄粉在地层中的分布说明，麻黄在过去曾遍布我国各地，发现的最早时期是在侏罗纪，到白垩纪─早第三纪时，种类较现在丰富，将近５０种。依据麻黄粉在世界各地地层中的分布和时期，结合大陆飘移和海底扩张板块构造学说推断，原麻黄在各大陆板块先后分离之前已经发生与演化。因此，在我国同藤麻黄亚组一样来源于原麻黄的膜果麻黄组也是相当古老，其代表种在亚洲中部形成了荒漠的分布中心；而在喜玛拉雅和横断山区则是麻黄亚组的种类衍生发展起来的次生中心。

The genus Ephedra in China includes 15 specics,2 varieties and 1 form belong to Sect.Alatae and Subsect.Ephedra of Sect.Ephedra.These species distribute in all parts of China except for the provinces located in Pearl River valley and median and lower and lower part of Yangtse River valley.The Ephedripites occurred in layers of China show that the genus Ephedra distributed in all parts of China with about 50 species,its earliest appearance in Jurassic and rich in species in Cretaceous and early Tertiary.According to the Ephedripites distribution in the world and the theory of continent driftion and ocean floor spreading-plate tectonics.The process of speciation of primitive species in Ephedra had occurred before the split of the ancient Pangaea. Like the Subsect Scandentes originated form Protoephedra Sect.Alatae are also ancient and has its centre in the deserts of Central Asia.Its secondary centre of species speciation is in Himalaya and Hengduan mountains.