A new species of the medullosan seed fern genus, Pachytesta, is
described from specimens discovered in coal balls from Iowa. The specimens
used in this study were located in coal balls, which are concretions of ancient
permineralized peat. Anatomical study of the new species was made possible
through the use of mounted cellulose acetate peels and photomicroscopy. The
ovule is approximately 5.0-5.5 cm long and 2.4 -2.8 cm wide at its mid point. The
integument contains a sarcotesta with 12 vascular bundles, a sclerotesta of
radiating fibers and variable thickness, and an endotesta consisting of a thin
cuticle. The primary ribs of the ovule are commissured. Based on the anatomical
features studied, Pachytesta sp. A. is most similar to Taylor’s (1965) P.
olivaeformis, P. composita, P. illinoensis group and is potentially a member of
this group.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1521 |
| Date | 15 May 2009 |
| Creators | McCarty, Mary Rachel |
| Contributors | Raymond, Anne |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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