Pyroxene-phyric basalts constitute a distinct petrologic group in samples from lunar maria at both Apollo 12 and Apollo 15 sites. Textures of pyroxene-phyric basalts from both sites are similar, but bulk compositions and mineralogy are somewhat different. Pyroxene-phyric basalts are characterized by large pyroxene phenocrysts with cores of magnesian pigeonite and mantles of augite grading to ferroaugite, usually set in a distinctly finer groundmass of iron-rich pyroxene, plagioclase, ilmenite, and other minor minerals. Olivine is scarce or absent modally and normatively. Controversy has arisen over whether the porphyritic texture is a result of (1) a two-stage cooling history, e.g. phenocrysts formed at depth, and groundmass formed on extrusion; or (2) single stage, rapid cooling under supercooled conditions (cooling history here refers to cooling conditions imposed by external factors, and is not to be equated with ‘crystallization history’). A study of six rocks belonging to this group from Apollo 15 rake samples is reported here. A considerable range of textures is present in these rocks, and they may be ranked in order of decreasing late-stage cooling rate (15125, 15666, 15682, 15118, 15684, 15116) on the basis of groundmass crystal size. The same ranking is obtained from delta-beta (measured in X-ray precession photos) of pigeonite and augite exsolved from once homogeneous crystals, or of epitaxially overgrown augite and pigeonite.