Morfología de plántulas de Bursera Jacq. ex L. (Burseraceae) y sus implicaciones filogenéticas

Characters of seedlings from ten species of the genus Bursera were studied, in order to find additional taxonomic evidence. All species showed phanero-epigeal germination, developing a primary root system (axonomorphous root). Species included in section Bursera have a root swelling at basal level near the collar, and a slim hypocotyl. The cotyledonary leaves were multilobate in the ‘cuajiotes’ species group and three-lobed in species of B. simaruba complex. The species of Bursera sect. Bullockia showed a not swollen primary root system with a slim collar; a striate, lenticelled and swollen hypocotyl, and three-lobed cotyledonary leaves. There are four characters that can be considered important for phylogenetic analyses: (1) protophyll margin type, (2) protophyll venation, (3) form of cotyledonary leaves, and (4) the swolliness of the radicle. Groups like section Bullockia, the ‘cuajiotes’ and ‘mulatos’ are supported upon the distribution of characters.