The forthcoming Polygalaceae treatment for the “Flora de la República de Cuba” will recognize four shrubby Polygala species instead of the eight that had been previously described. One of them is P. guantanamana, easily recognized by its glabrous pedicels. A broadly based revision permits to distinguish two subspecies in it. P. guantanamana subsp. guantanamana is found in coastal habitats of southeastern Cuba and in xeric vegetation, mostly on ophiolithic soils, in central and western Cuba. The newly described subsp. alternifolia grows in that same kind of inland habitats but is limited to eastern Cuba. P. scabridula, a characteristic morph which is limited to and prevalent but not exclusive in the central and western Cuban populations, is given varietal rank within subsp. guantanamana.