STUDIES IN THE ANATOMY AND MORPHOLOGY OF THE POLYGONACEOUS FLOWER

Abstract

UP TO recent times the families of the angiosperms have been studied mainly from a taxonomic point of view. To some extent the morphological and anatomical aspects have been considered, but both of these mostly in a gross and external way. The observations made in such studies have been used extensively by different workers to organize a phylogenietic plan of development within the groups of flowering plants. For the most part, these observations have been incomplete and fragmentary, and interpretations of the known facts have been various. With some of the fundamental and critical facts lacking, the conclusions reached are subject to revision or verification. Much of the work does not have a firm foundation; too much has been based on hypothesis rather than on facts. If a more satisfactory phylogenetic picture of the flowering plants is to be gained, both the internal and external structure of the flowers must be studied. Not only should this study be made grossly, but also minutely. Especially is this true of the flower, the part of the plant which has been particularly emphasized in modern classification. It was not until a few years ago that much intensive work was done on internal floral morphology and anatomy. Van Tieghem, Henslow and a few others made a good start, but they were greatly handicapped in their work by crude equipment; their understanding was good but relatively rudimentary. With present-day equipment and methods, a more complete knowledge of the structure of plants can be worked out, and from the facts obtained, hypotheses, both old and new, can be substantiated or discarded. It was from this standpoint that the author began his work on the polygonaceous flower. Much work had been done on the Polygonaceae but little upon the floral anatomy. It is hoped that the facts revealed in the anatomical and morphological structure of the polygonaceous flower may prove valuable in determining the relationship of the group. FLORAL, STRUCTURE.-The Polygonaceae is generally considered to consist of about 30 genera, embracing roughly 700 species. For a family of such size and distribution, its members show unusual homogeneity in floral makeup, indicating a natural grouping. Most of the members of the group have perfect flowers, the dioecious condition appearing in a few genera only. The number of perianth parts can be used conveniently to subdivide the family into two main