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GEOREF RECORD

Tertiary prairie grasses and other herbs from the High Plains

Maxim Konrad Elias
Tertiary prairie grasses and other herbs from the High Plains
Special Paper - Geological Society of America (November 1942) 51 (12, Part 2): 176 pp.

Abstract

Seeds of the late Tertiary prairie grasses are fairly common throughout the most arid parts of the Prairie States. The most common among these fossil seeds show close relation to the most typical modern prairie grass: the spear-grass or Stipa, which has world-wide distribution. The oldest known ancestor of this grass was found in the Harrison formation of lower Miocene in western Nebraska. Another prairie grass, a millet (Panicum), and one of its kin (Setaria) appeared here only in the Pliocene, when the prairie was also invaded by numerous borage herbs, ancestors of modern Lithospermum, Krynitzkia, and Lappula, which are now also very common among the forbs of the plains. The preservation of the protective covers of the fossil seeds is so nearly perfect that some fine morphologic details, previously undescribed for Stipeae, were for the first time detected on the fossil Stipidium and subsequently on some species of its living descendant, STIPA: Comparative study of the fossil and living forms reveals evolutionary trends of the seeds of the prairie grasses. The rather small and generalized Miocene ancestor gave rise to greatly diversified Pliocene and Recent species. The seeds of these include small and very large, very slender, and very stout forms, all of them variously adapted for protection against drought and for more efficient dispersal. Abundance, good preservation, and rapid ecologic and evolutionary changes make grass seeds the best index fossils for subdivision of the continental late Tertiary rocks.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 51
Serial Issue: 12, Part 2
Title: Tertiary prairie grasses and other herbs from the High Plains
Author(s): Elias, Maxim Konrad
Published: 194211
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 978-0-81372-041-8
Number of pages: 176
Accession Number: 1949-004805
Categories: Paleobotany
Document Type: Serial
Bibliographic Level: Monographic
Illustration Description: illus. incl. index map
N29°00'00" - N56°00'00", W115°00'00" - W97°00'00"
N40°00'00" - N43°00'00", W104°04'60" - W95°19'60"
Source Note: 41; abs., Bull., p. 1969, Dec 1, 1940; Am. Jour. Botany, Suppl. p. 8, Dec. 1941.
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2021, American Geosciences Institute. Reference includes data from Bibliography and Index of North American Geology, U. S. Geological Survey, Reston, VA, United States
Update Code: 1949
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