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Osmunda pluma
Osmunda pluma C.N. Mill. Contr. Mus. Paleontol. Univ. Michigan, 21(8): 150. 30 Jun 1967
- Name
- Osmunda pluma
- Rank
- Species
- Generic Name
- [Genus] Osmunda
- Authors (Pub.)
- Miller C. N., Jr.
- Publication
- Evolution of the fern genus Osmunda [1967/6]
- Journal
- Contributions from the Museum of Paleontology, University of Michigan
- Volume
- 21
- Issue
- 8
- Page number
- 150
- Year
- 1967
- Fossil Status
- rhizomata
- Stratigraphy
- Paleocene
- Strat. comment
- Fort Union Formation
- Location
- Morton County, North Dakota, USA
- Paleoregion
- America (North)
Data for Holotypus
- Repository
- Museum of Palaeontology, University of Michigan, Ann Arbor, USA
- Repository Number
- 52157
Data for Paratypus
- Repository
- Museum of Palaeontology, University of Michigan, Ann Arbor, USA
- Repository Number
- 52158
- Diagnosis
- Petrified rhizomes about 2-4.5 cm. in diameter, consisting of a stem about 7.0 mm. in diameter surrounded by a mantle of closely adhering petiole bases; xylem cylinder of stem about 2.5 mm. in diameter, 0.75 mm. thick, and consisting of 7-12 strands as observed in transverse section; leaf-gaps high and wide, formed immediately opposite each departing leaf-trace; phloem a continuous cylinder around the xylem; endodermis external only; cortex consisting of a thin inner parenchymatous zone and a thick outer fibrous zone, together including 6-1 1 departing leaf-traces in a given transverse section; leaf-trace endarch, separating from stem xylem with a single protoxylem which bifurcates as leaf-trace passes through inner cortex; petiole base stipular, sclerenchyma ring hetero- geneous, containing an abaxial arch of thick-walled fibers which splits just above stipular region to form two lateral clusters; inner cortex of petiole base containing scattered clusters of thick-walled fibers; stipular expansions containing an elongate strip of thick-walled fibers near base of stipular region, and separate patches of fibers in linear series above; roots with diarch xylem strand, separating from leaf-trace as latter diverges from stem xylem.
