Relationships among gymnospermous pollen

Depositional cyclicity and paleoecological variability in an outcrop of Rio Bonito formation, Early Permian, Paraná Basin, Rio Grande do Sul, Brazil

“…Concepts provided by Gould and Delevoryas (1963), Staplin et al (1967), Taylor and Taylor (1993) and Balme (1995) were adopted for botanical affinity inferences. In relation to the algae and algae-like elements, taxonomic determinations and paleoecology were based mainly on Hemmer and Nygreen (1967), Loeblich and Tappan (1976), Tiwari et al (1994), Guy-Ohlson (1992), Elsik (1996), Batten (1996) and Servais (1996).…”

Redescription of some fossil gymnospermous pollen (Chasmatosporites, Marsupipollenites, Ovalipollis)

“…The sulcoid leptoma of these genera is always clearly delineated, either elongate oval in outline or "keyhole-shaped" (constricted at its midpoint with rounded extremities), and normally is flanked by well-developed sexinal lips; this type of sulcus is also shown by pollen of the Cycadaceae. Staplin, Pocock, and Jansonius (1967) considered that this type of pollen "possibly was close to the evolutionary line that gave rise to the Cycadicae and Pinatae", and termed this particular type of sulcoid leptoma "cycadoid".…”

“…as well as more or less developed tulae. Staplin, Pocock, and Jansonius (1967) postulated a late Paleozoic primary group of gymnospermous ancestors from which seven major lineages of gymnospermous plants developed, each with its own pollen characteristics. Morphological evolutionary trends in one lineage often parallel those in others, possibly resulting in the interpretation of closer affinities than may have existed in actual fact.…”

“…Systematic Descriptions During the preparation of a paper on phylogenetic relationships of fossil gymnospermous pollen (Staplin, Pocock, and Jansonius 1967), we examined the morphology of a number of form genera. Among these, our descriptioils of Chasmatosporites, Marsupipolle~~ites, and Ovnlipollis contained details that warrant further discussion.…”

In Situ Gymnosperm Pollen From the Middle Jurassic of Yorkshire

“…It ranges at least from the Lower Lias to almost the top of the Cretaceous (Staplin, Pocock and Jansonius 1967 and Deltolepis calyptra Harris-scale leaf-), from the Lower and Middle Deltaic Series,seeTHOMASet Harris(1960) and Harris (1964). (Couper 1958, Potoni£ 1962, Nilson 1958, Burger 1966, Staplin, Pocock and Jansonius 1967 Callialasporites rimalis (with a thick brim around a "body" with folds) and C. triletes (with a clear tetrad scar). Muir (1964) Gamerro (1965).…”