Detecting ontogenetic stages of the palm Attalea humilis in fragments of the Brazilian Atlantic forest

A study of the ontogenetic stages of the acaulescent palm Attalea humilis M art. ex. Spreng was conducted in three fragments (1.6, 6.4, and 9.9 ha) of the Atlantic forest in southeastern Brazil. The fragments were damaged by f ire during the study period (1996-1999). External macromorphology and quant itative measures of leaf number and length of the newest leaf's rachis allo wed the distinction of five ontogenetic stages. Seedlings were attached to buried fruit remains and presented entire leaves. Juveniles possessed incom plete segmentation of the blade. Pinnatifid-leafed, non-reproducing individ uals were morphometrically divided in two groups: immature, with fewer leav es and smaller but highly variable youngest leaf length, and virginile, wit h more and larger leaves, but more constant youngest leaf length; the criti cal crown size by which immature and virginile stages could be identified v aried according to fragment and year. Reproductive palms bore identifiable reproductive structures. Seedlings, juveniles, and immatures had fewer leav es than virginile and reproductive individuals. Leaf length was similar bet ween seedlings and juveniles but increased in later stages. The characteris tics of each stage were fairly constant throughout the study years in the t hree fragments and were little affected by fire, indicating that the stages we define in this study are important in the developmental program of A. h umilis.