Hybridization between Psidium guajava and P. guineense (Myrtaceae)

Psidium guajava andP. guineense are characterized, illustrated and contrasted. Population samples ofPsidium guajava andP. guineense and apparent hybrids were collected from four localities: two in Mexico, one in Honduras, and one in Argentina. Seven morphological characters, one micromorphological (stomatal density), and one chemical character (presence or absence of myricetin) that distinguish the parent species were found to be useful in the evaluation of specimens and population variation. Results were consistent with the hypothesis that hybridization occurs between these species, but in three localities it may not go beyond Fl ’s. Back crossing between hybrids andP. guajava was not detected at any locality.