IMPLICATIONS OF RBCL SEQUENCE DATA FOR HIGHER-ORDER RELATIONSHIPS OF THE LOASACEAE AND THE ANOMALOUS AQUATIC PLANT HYDROSTACHYS (HYDROSTACHYACEAE)

Subclass and ordinal relationships of Loasaceae, a small predominately New World family, are examined using rbcL sequence data. Sequences we re examined for eight of the fifteen genera of the Loasaceae and the m orphologically anomalous aquatic genus Hydrostachys (Hydrostachyaceae) . Parsimony analyses of these sequences, combined with previously publ ished rcbL data, indicate that Loasaceae belong in the Cornales, and a re the sister group of Hydrangeaceae. This agrees with phylogenies bas ed on chloroplast DNA inverted repeat restriction site, morphological and chemical data. The rbcL trees support the monophyly of the Loasace ae and most generic relationships correspond to current subfamily divi sions. The rbcL phylogeny also provides the first suggestion that Hydr ostachys is allied with the Hydrangeaceae in the Cornales.