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Thalassites parkavonensis
Thalassites parkavonensis Benzecry, Brack-Hanes Bot. J. Linn. Soc., 157(1): 24. 28 Apr 2008
- Name
- Thalassites parkavonensis
- Rank
- Species
- Generic Name
- [Genus] Thalassites
- Authors (Pub.)
- Benzecry A.
Brack-Hanes S. D.
- Publication
- A new hydrocharitacean seagrass from the Eocene of Florida [2008/4]
- Journal
- Botanical Journal of the Linnean Society
- Volume
- 157
- Issue
- 1
- Page number
- 24
- Year
- 2008
- Fossil Status
- rhizomata
- Stratigraphy
- Eocene
- Strat. comment
- Avon Park Formation, Claiborne Stage
- Location
- Florida Rock Industries dolomite/limestone quarry, approximately 1.5 miles south of Gulf Hammock (sec. 28, T14s, R16s), Levy County, Florida, USA
- Paleoregion
- America (North)
Data for Holotypus
- Repository
- Eckerd College Herbarium, Palaeobotanical Collection, St.-Petersburg, USA
- Repository Number
- AP Series #267A & B (part and counterpart) and APS Series 267A.
- Diagnosis
- Dimorphic rhizome system with striated, monopodial, plagiotropic rhizome 5–10 mm in width; internodal distance constant (10–12 mm); closed annular scars at nodes and fine, straight, unbranched roots infrequent at internodes; epidermis of differentially thickened elongate cells in files parallel to the long axis, cortex spongy. Orthotropic, bifurcated, short shoots about 3–6 mm wide in pairs every three to five nodes. Epidermis of short shoots with differentially thickened, almost isodiametrical (cuboidal) cells and a cuticle; spongy cortex with longitudinal bundles of fibres; crystals and tannins abundant. Terminal clusters of six to eight, strap-shaped, eligulate leaves almost encircle short shoots in alternate and distichous arrangement. Non-fibrous leaf blades (15–19 mm wide) have entire, smooth margins and rounded apices. Leaf venation parallel (27–30 veins) with perpendicular and oblique cross veins. Median vein is prominent. Fibrous, amplexicaulous, basal leaf sheath (15–19 mm wide and 30–45 mm long) is persistent. Leaf epidermal cells are elongate to cuboidal and have straight, thin walls. Tanniferous cells are profuse and in circular aggregations. Crystals are abundant.
