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PALEOZOIC SEED STUDIES: A NEW PENNSYLVANIAN PACHYTESTA FROM SOUTHERN ILLINOIS
Author(s) -
Taylor Thomas N.,
Delevoryas Theodore
Publication year - 1964
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1964.tb06619.x
Subject(s) - pennsylvanian , biology , integumentary system , apex (geometry) , paleozoic , paleontology , botany , anatomy , structural basin
Pachytesta stewartii, a new species found in Middle Pennsylvanian coal ball deposits in southern Illinois, is 2.5 cm long and approximately 1.5 cm in width at its greatest diameter. Commissured ribs are pronounced near the apex and progressively less distinct toward the base. The integumentary system is delimited into 3 regions: outer sarcotesta, middle sclerotesta, and thin endotesta. Conspicuous in the new species is a pronounced basal extension with an enclosed chamber that may be the result of decomposition of thin‐walled parenchyma cells. Relationships with other species and possible significance of the chalazal chamber are discussed.