Anatomical Studies on Seeds and Seedlings of Some Utricularia (Lentibulariaceae)

Abstract

The undifferentiated mature embryos of someUtricularia studied consist of large polygonal cells which contain many starch grains. Later, they consist mostly of large polygonal cells with some small cells in one or more regions adjacent to the seed coat, which lack starch grains but have rather easily visible nuclei. After these small cells divide and produce more cells of the same type toward the midcenter of the embryo, they form one or more primordia which grow into the primary structures of the seedling. The primordia of the embryo seem to have no pattern as to which primary vegetative structure they will develop into. However, the terrestrial species ofUtricularia studied showed some non-cotyledonous, primary differences in germination patterns; some form primary foliar units, some form stolons, and some form bladders. The first and second primary foliar units of aquaticUtricularia radiata andV. gibba subsp.gibba do not follow in the same manner as cotyledons. No cotyledon could be distinguished in any of theUtricularia seedlings studied. In the seedlings ofU. gibba subsp.gibba andU. radiata, appearance and differentiation of the vascular elements occur simultaneously in more than one direction, toward the meristematic tissues of primary vegetative structures and toward the midcenter of the embryos. Lloyd’s proposed term: “cotyledonoids” (1942) and that of Kumazawa: “cotyledons” (1967) should not be used for the first and second primary foliar units in either aquatic or terrestrial to terrestrial-epiphyticUtricularia, unless further supportive evidence is accumulated.