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TAXONOMIC CONSIDERATIONS FOR CARBONIFEROUS COALIFIED COMPRESSION EQUISETALEAN STROBILI
Author(s) -
Gastaldo Robert A.
Publication year - 1981
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.1537-2197.1981.tb07842.x
Subject(s) - bract , strobilus , biology , sporangium , genus , botany , carboniferous , paleontology , inflorescence , spore , structural basin
Equisetalean strobili normally are encountered as disarticulated organs. This condition has necessitated the creation of 12 form genera to accommodate the various morphological architectures and anatomical configurations. Taxonomically useful characteristics, which are discernable in permineralized specimens, are rarely distinguishable in coalified compressions due to their destruction during diagenesis and coalification. Therefore, genera established on the position of sporangiophore‐trace origin, such as Schimperia Remy and Remy, are untenable when dealing with coalified compressions. Although the two largest genera of strobili, Calamostachys Schimper and Palaeostachya Weiss, may be synonymous, it is proposed that these form genera be retained when dealing with coalified compression specimens. Each genus provides a particular architectural concept for specimens which may not be assignable to the species level. Calamostachys and Palaeostachya are highly overspeciated genera. It is suggested that characteristics necessary to delimit new species include bract height, degree of bract fusion, disposition of bracts, bract: sporangiophore ratio, number of sporangia per sporangiophore, and sexual status.