A morphological and embryological study of Callicoma serratifolia Andr. (Cunoniaceae).

Abstract

The morphological and anatomical features of Callicoma serratifolia populations on the New England Tablelands reveal the existence of two distinct groups, here designated A and B. Major morphological differences between these groups include leaf margin serration, distribution of hairs on stems and branches, possession of one trichome type in group A in contrast to two types found in group B, overall leaf size and venation patterns. At the anatomical level the differences are in vessel dimensions and the number of bars on perforation plates. Features common to both groups include bisexual, pentamerous and apetalous flowers, tetrasporangiate versatile anthers with a glandular tapetum, simultaneous cytokinesis in pollen mother cells and colporate pollen which is released at the 2-celled stage. The ovules are anatropous, bitegmic and crassinucellate with a polygonum type of embryo sac development. The endosperm is of the nuclear type. Both integuments contribute to the formation of the seed coat. The embryo is straight. While in its vegetative anatomy C. serratifolia resembles members of the families Eucryphiaceae, Saxifragaceae and Escalloniaceae, embryologically it closely resembles Baueraceae and less closely the subfamily Hydrangeoideae of the Saxifragaceae.