Molecular Phylogeny of Rhizophoraceae Based on rbcL Gene Sequences

rbcL

sequences to clarify the inter- and intrarelationships of Rhizophoraceae which have been variously discussed. The analyses included 12 of the 15 genera of Rhizophoraceae (4/7 of Macarisieae, 4/4 of Gynotrocheae, and 4/4 of Rhizophoreae) and a few putatively related taxa, including two of the four genera of Anisophylleaceae. The most parsimonious trees supported the monophyly of Rhizophoraceae as well as each of the three traditionally recognized tribes Macarisieae, Gynotrocheae, and Rhizophoreae. The family Rhizophoraceae is a sister taxon to Erythroxylum (Erythroxylaceae) and is further closely related to Byrsonima (Malpighiaceae), Passiflora (Passifloraceae), Turnera (Turneraceae), Ochna (Ochnaceae), Drypetes (Euphorbiaceae), and Humiria (Humiriaceae). Anisophylleaceae, which have often been included in Rhizophoraceae as a tribe or subfamily, are placed in a common clade with Begonia (Begoniaceae), Cucurbita (Cucurbitaceae), Coriaria (Coriariaceae), Corynocarpus (Corynocarpaceae), Datisca (Datiscaceae), Tetrameles (Datiscaceae), and Octomeles (Datiscaceae). Within Rhizophoraceae the mangrove tribe Rhizophoreae is sister to the inland tribe Gynotrocheae, with inland tribe Macarisieae positioned as a sister taxon to these two tribes. This pattern of relationships within the family basically agrees with those suggested by cladistic analyses based on morphological characters, except that Gynotrocheae are monophyletic with Crossostylis as a derived taxon within the tribe in the present study. Based on this cladogram for Rhizophoraceae, we discuss evolutionary trends of a few ecological and morphological characters, including the formation of aerial roots and the ovary position.