We compared the phenology of three native Cerrado grasses at two levels of plant organization: number of leaves per tiller and number of tillers per plant. The C4 Axonopus marginatus (Trin.) Chase and Trachypogon spicatus (L.f.) Kuntze and the C3 Echinolaena inflexa (Poir.) Chase were studied in the IBGE Ecological Reserve in Brasília, Distrito Federal, between November 1996 and June 1998. Tiller phenology was compared in three plant communities: "Cerrado denso" protected from fire for 26 years, "campo sujo" protected for 22 years and "campo sujo" burned every other year. Leaf phenology was studied in the protected "cerrado denso" only. The number of leaves of the C3 species was always greater than the C4 species. Leaf area was constant through time in the C3 species but decreased in the C4 species during the dry season. For A. marginatus and E. inflexa the number of tillers per plant was greater in the protected "campo sujo", followed by the "cerrado denso" and the burned "campo sujo". The number of tillers of T. spicatus in the protected "campo sujo" was twice the number of tillers in the burned "campo sujo"; burned "campo sujo" did not differ from the "cerrado denso". The phenological differences between species were most evident at the leaf level. Fire caused the simplification of plant architecture (number of tillers) in all species.
leaf phenology; tiller phenology; savanna; Cerrado; grasses
