Abstract: The term of remnant morpheme is defined when people extract the morphemes with the method of remnant comparison. The academic circles have already reached an agreement on the existence of the remnant morphemes. But there remains a big controversy about the nature, reasons of emergence and ways of wordbuilding of the remnant morphemes. This paper discusses this linguistic element with the example of the doubletone compound nouns in Chinese plants from the angle of linguistic history. The remnant morphemes are bound that build up words weakly in synchronic linguistics and the accumulation in the historical development of language. The remnant morphemes in the doubletone compound nouns in Chinese plants are those morphemes with the explicit denotation. The onomastic names of the plants which come from the semantic succession and the differentiation of words forms and structures are the main reason of formation of the remnant morphemes. The major ways of building up words involving the remnant morphemes are setting the modifying morphemes before and specific morphemes after.