Myrmekite, an intergrowth between vermicular quartz and sodic plagioclase,often occurs in minor amounts in felsic intermediate-acidic intrusive and gneissic rocks. Several hypotheses for myrmekite genesis are briefly reviewed. The proportionality relationship between the amount of vermicular quartz and the composition of plagioclase in myrmekite or the Ca content of the rocks is consistent with hypotheses of replacement, solid-state exsolution, and recrystalli-zation of primary plagioclase. The presence of perthitic albite and even K-feldspar relicts in the myrmekite obviously indicates that the myrmekite is formed by replacement of Ca-bearting sodic solution or emanation after K-feldspar.Therefore, myrmekites of different morphology and spatial distribution are of the same metasomatic origin. The myrmekite formed during the deformation period should be later than that formed during the pre-deformation period.