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OBSERVATIONS ON THE ONTOGENY OF LEPIDOCARPON
Author(s) -
Balbach Margaret Kain
Publication year - 1962
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.1537-2197.1962.tb15037.x
Subject(s) - sporangium , biology , pennsylvanian , ontogeny , pedicel , taxon , apex (geometry) , paleontology , devonian , anatomy , botany , genetics , spore , structural basin
B albach , M argaret K ain . (U. Illinois, Urbana.) Observations on the ontogeny of Lepidocarpon . Amer. Jour. Bot. 49(9): 984–989. Illus. 1962.—This paper is a description of an apical fragment of a petrified Lepidocarpon cone of middle‐Pennsylvanian age from Illinois. Prior to the discovery of this cone, no evidence was available as to the origin of the lateral laminae (“integuments” of Scott, 1901) which enclose the megasporangium. This cone apex, however, shows very young sporangia in successive stages of development and the laminae can be seen to arise from the lateral margins of the pedicel at an early stage in ontogeny. The laminae are present to a recognizable degree even in the youngest sporangia in the upper levels of the cone. Sporangia in the successively lower levels show a progressive envelopment by the laminae; growth of the latter appears to have been synchronous with that of the sporangium. This finding warrants an emendation of that part of the original diagnosis of the genus (Scott, 1901) which describes the immature stage as lacking the lateral laminae. The suggestion also is made that those unintegumented forms included by Scott in the taxon Lepidocarpon lomaxi may actually have been monosporate, megasporangiate, lepidostroboid sporophylls, and, hence, they should be considered to be a separate taxon.