Abstract: Author provides, in the paper, that the Calamaceae is a transitionary Family, from Subfamily, Calamoideae of Palmae, by covering the reflexing spirally scales, which are diferrent from Palmae, on ovaries and fruits. The Ancestor of Palmae, Pro-Palmae, perhaps, was derived, in Cretaceous Period, from a branch of the evolution trunk from Caytoniales to Pro-Cycadales in Carboniferous Period according to the materials of fossial and pollen grains of Paleobotany, and the ancestor of Calamaceae, Pro-Calamaceae, perhaps, was derived from the branchlet on the evolution branch to the Palmae in later Cretaceous Period. Both Palmae and Calamaceae, especially the former, maybe, is one of the most primitive families of Angiospermae, especially inMonocotyledoneae. In Palmae the Phytelephantoideae and Coryphoideae should be the most or more primitive groups, and Arecoideae and Ceroxyloideae are more advanced groups. But Nypoideae, perhaps, is the most advanced and specialized one, even the ancestor of it, perhaps, was derived from Pro-Phytelephantoideae, In Calamaceae, the Calamoideae is more primitive one than the Lepidocaryoideae. Author also discusses the characters of floristics of two families. Although they are pan-tropic distribution, only a few genera of them are extended to warm and central subtropical areas in both North and South Hemispheres. The margin of distribution are extended to the Yangtze River Valley and the South of the lower reaches of Yellow River of China, Central of Japan, California and Florida of USA and the North of Mediterrenian areas in North Hemisphere, and to Central of Chile and South of New Zeyland in South Hemisphere. The present distributional center are in tropical and warm subtropical areas of Asia, Central and South America, Oceania and Africa. The mass center of it is in Tropical Asia, Tropical Central and South America, South Pacific Archipelagoes and S.-E. Africa. Finally, author introduces in the past 50 years more than 400 species of two families have been introduced and acclimatized in S., S.-E. and S.-W. China, except the native species in China. Some cold-resistant species were introduced into the Yangtze River Valley or even more northern areas. Most species, in above mentioned, are in the important economic uses, such as 1. The eadables, included the starch from pith and juice from trunk or inflorescences for food, or making sugar, wine, vinegar or drink, or isolated oil from fruits or seeds for eating or for industral uses. Some berries and drupes are used for eating fruits, and some tender buds are for vegetables. Also a few seeds are the substitutors of Coffe. 2. Medicinal uses, which included many species are for the antiphlogistic, the anthelmintic, the haemostatic or invigorating the circulation of blood and for anti-cancers;3. Constructions, included that some timbers are for building the common houses, bridges, boats;abstracting wax is for industral or civil uses;fibres-for weaving thick cables or ropes and rugs, and others are for making the handicrafts, and articles of everyday uses;4. Gardening, those are used for building the tropical scenic spots, beautifing the gardens and residential quarters or constructing the landscape ecology etc.

Key words: Palmae, Calamaceae, systematics, evolution, floristics, economic uses