Evolutionary history of plants seed model is shared by basically all gymnosperms (literally: "naked seeds"), most of which encase their seeds in a woody cone or fleshy aril (the yew, for example), but none of which fully enclose their seeds. The angiosperms ("vessel seeds") are the only group to fully enclose the seed, in a carpel. Fully enclosed seeds opened up a new pathway for plants to follow: that of seed dormancy. The embryo, completely isolated from the external atmosphere and hence protected from desiccation, could survive some years of drought before germinating. Gymnosperm seeds from the Late Carboniferous have been found to contain
Sub-provincial division out of Sichuan altogether. Xinjiang Production and Construction Corps also has the powers of a sub-provincial city. Chengdu is the largest sub-provincial municipality; has a population exceeding that of the independent municipality of Tianjin while, both Harbin and Chengdu have a bigger area than Tianjin. Additionally, the head of Pudong New Area of Shanghai and Binhai New Area of Tianjin, which is a county-level district, is given sub-provincial powers. The National Joint Conference of Sub-provincial City People's Congress Standing Committee Chairpersons () are attended by the chairpersons and vice-chairpersons of all sub-provincial cities. It was proposed by the Guangzhou Municipal