Fern classification is in a state of flux, the largest area of disagreement being the family Polypodiaceae (Wagner, 1959). This polyphyletic group (Eame, 1936) has been divided by several prominet workers into many families. Ching (1940) recognized thirty-two, Holttum (1947) five, and Copeland (1947) nine families. Munz and Keck (1959) divided the old famliy Polypodiaceae, as represented by the ferns of California, into five families. The classification of Munz and Keck is the most recent treatment in this paper. Historically, classification of the leptosporangiate ferns has been based on the sorus, but the last half century has seen greater use vegetative characters. Problems of phylogenetic relationships can only be solved by the study of a number of features from all aspects of the planet. The more characters considered and evaluated, the more accurate and valuable are the conclusions.
This line of reasoning has been pursued fruitfully in other plant groups as exemplifed by Metcalfe (1960) in his work on the anatomy of the monocotyledons. In this work the microscopical characters of the lamina were taken as being of major importance because of eary availability and the fact that one does not have to have the plant in flower before investigations can proceed.
Another important reason for studying vegetative characteristics is that they are often preserved in the fossil record. Black (1929), Odell (1932), Florin (1951), and Greguss (1961) have studied cutinized superficial leaf epidermis preserved as fossils. The work of Florin has been particularly important in clarifying the phylogeny of the living conifers
The questions of the value of the epidermis in the study of the ferns still remains unsolved problem. Therefore, it is the intention of this paper to explore the possibility of using epidermal charaters as a basis for establishing patterns of morphological and taxonomic significance. Because of their easy availability, the native ferns of California were used for this study.
| Identifer | oai:union.ndltd.org:pacific.edu/oai:scholarlycommons.pacific.edu:uop_etds-2632 |
| Date | 01 January 1967 |
| Creators | Hebert, Lorraine Martin |
| Publisher | Scholarly Commons |
| Source Sets | University of the Pacific |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | University of the Pacific Theses and Dissertations |
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