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Unformatted text preview: Lycophyta - 1 Lycophyta (Lycopodiophyta) Members of the Lycophyta were once abundant on earth. There are extensive fossil records of these vascular plants, and their decomposing bodies produced much of today's fossil fuels. Fossil Lycophytes ranged up to 100 feet tall. Today there are ten to fifteen genera in the Lycophyta; none are dimensionally impressive. There are about 700 species of Selaginella , 400 species of the Lycopodiae genera, and fewer of the elusive Isoetes . Representatives of all three classes of the Lycophytes are found in Washington and the Pacific Northwest. Each class has unique morphological features so that it is not easy to discuss the Phylum. They do share some features however. The three classes in the Lycophyta are: Lycopodiae Genera: The Lycopodiums are classified into 10 15 genera including Lycopodium, Huperzia and, Diphasiastrum . We will not discuss the different genera. (Lycopodiums are commonly called ground pines and club mosses) Selaginellae Genus: Selaginella (Commonly called club mosses or spike mosses) Isoetae Genus: Isoetes (Commonly called quillworts) Characteristics of the Lycophyta The Lycophyta have vascular stems and adventitious, vascular roots. They have microphylls, leave with a single vascular trace (one vein). In most Lycophyta the leaves are spirally arrange along the stem. Some Selaginella species have 2 or 4- ranked leaves and some Lycopodiums and Selaginella species have flattened stems and leaves. The sporangia are located in the axils of modified leaves, called sporophylls (spore-bearing leaves). The sporangia may be axillary, along the stem or...
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- Spring '09