Seed are sometimes sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. Different groups of plants have other modifications, the so-called stone fruits (such as the peach) have a hardened fruit layer (the endocarp) fused to and surrounding the actual seed. Nuts are the one-seeded, hard-shelled fruit of some plants with an indehiscent seed, such as an acorn or hazelnut. Seeds are produced in several related groups of plants, and their manner of production distinguishes the angiosperms ("enclosed seeds") from the gymnosperms ("naked seeds"). Angiosperm seeds are produced in
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