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Betula hesterna
Betula hesterna L.J. Hickey Mem. Geol. Soc. Amer., 150: 120. 19 Jul 1977
- Name
- Betula hesterna
- Rank
- Species
- Generic Name
- [Genus] Betula
- Authors (Pub.)
- Hickey L. J.
- Publication
- Stratigraphy and paleobotany of the Golden Valley Formation (Early Tertiary) of Western North Dakota [1977/7]
- Journal
- Memoirs of the Geological Society of America
- Volume
- 150
- Page number
- 120
- Year
- 1977
- Fossil Status
- leaves
- Stratigraphy
- Thanetian
- Location
- White Butte, Stark County, North Dakota, USA
- Paleoregion
- America (North)
Data for Holotypus
- Repository
- National Museum of Natural History, Smithsonian Institution, Washington, USA
- Repository Number
- USNM 43180
Data for Paratypus
- Repository
- Princeton University, Princeton, USA
- Repository Number
- PU 20069 [pl. 16: 2], 20070 [pl. 15: 11]
- Diagnosis
- Leaves elliptic to ovate; I 5.5 to approximately 9.5 cm; w 3 to 5.3 cm; l/w
ratio 1.4 to 2.3; apex apparently acute; base acute to cuneate; margin irregularly doubly serrate. Petiole missing; leaf texture chartaceous and apparently rough. Venation pinnate, simple craspedodromous; Midvein stout, straight, with high relief; secondaries in 10 pairs; angle of divergence 45° to 70°, average 50°; stout, following a straight course to the margin where they are slightly upturned before entering the teeth; occasionally branched; teeth
from 4 to 6 per middle secondary vein. Tertiary veins originating at nearly right angles on either side of the secondaries; percurrent, forming an S-shaped curve; arrangement opposite on either side of the intercostal area; tertiaries frequently merging into the reticulum of the higher order venation; finer veins forming a reticulum; highest order of venation, seventh; highest order showing excurrent branching, fourth; areolation, equant and quadrangular; 0.3 to 0.7 mm in diameter, with freely ending veinlets.
Included provisionally within this species are woody catkins at the ends of alternately branched axes. In longitudinal section, these catkins are 0.5 cm broad, as much as 2 cm long and consist of an axis with bracts arising at right angles at intervals of 1 to 2 mm. Bracts thick and woody; they are straight for the first two-thirds of their length, then abruptly upcurved. These catkins may be distinguished from those of Platycarya by their widely spaced, abruptly upcurved bracts.
