[1] Univ Fed Rio Grande do Sul, Programa Posgrad Bot, Inst Biociencias, Av Bento Goncalves 9500, Porto Alegre, RS, Brazil
[2] Univ Republica, Fac Agron, Av Gral Eugenio Garzon 809, Montevideo 12900, Uruguay
[3] Univ Buenos Aires, Catedra Ecol, Fac Agron, Av San Martin 4453,C1417DSE, Buenos Aires, DF, Argentina
[4] Univ Sao Paulo, Inst Biociencias, Dept Bot, R Matao 277, Sao Paulo, Brazil
[5] Univ Buenos Aires, Fac Agron, IFEVA, Dept Metodos Cuantitat,CONICET, Av San Martin 4453,C1417DSE, Buenos Aires, DF, Argentina
[6] Univ Fed Pampa, Campus Sao Gabriel,Av Antonio Trilha 1847, Bage, RS, Brazil
[7] Univ Fed Santa Catarina, Dept Bot, Ctr Ciencias Biol, BR-88040900 Florianopolis, SC, Brazil