Unformatted text preview: group, using the former phylum name, Pterophyta. The earliest vascular plants have been reconstructed from the fossil record dating back about 425 million years, with branching sporophytes that were nutritionally independent of the gametophyte. The early vascular plants were small, as are the Bryophytes but their branching patterns provided a means of increasing complexity of the plant body and support for multiple sporangia. However, early vascular plants lacked roots or leaves. The ancestors of the Lycophyta, Equisetales and Psilotales, extant vascular plants often referred to as the "fern allies", were the first large land plants. Lycophytes and Equisetums are also prevalent in the fossil record. These vascular plant groups are not predominant organisms in our ecosystems today, substantially being replaced in ecosystems by seed plants. In contrast, the ferns, within the phylum, Pterophyta, are conspicuous in many ecosystems, including the Pacific Northwest....
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- Fall '09
- Plants, Fern, Pterophyta, Spore-Dispersing Vascular Plants