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A monograph of Dolerotheca Halle, and related complex permineralised medullosan pollen organs

Published online by Cambridge University Press:  16 November 2011

Gar W. Rothwell
Affiliation:
Department of Botany, Ohio University, Athens, Ohio 45701, U.S.A.
Donald A. Eggert
Affiliation:
Department of Biological Sciences, University of Illinois at Chicago, Box 4348, Chicago, Illinois 60680, U.S.A.

Abstract

Numerous permineralised, complex medullosan pollen organs are described from Middle and Upper Pennsylvanian sediments of North America. Together with a reinvestigation of type specimens for the previously described species, these provide the basis for fully characterising internal structure and external morphology, and for recognising structural homologies among all medullosan synangia. All medullosan pollen organs, simple and complex, can be interpreted as consisting of sporangial tubes that are embedded in parenchymatous and sclerenchymatous ground tissue, and that have vascular bundles within the parenchymatous tissue. The sporangial tubes are arranged in a single series, usually a ring, with parenchymatous ground tissues and vascular bundles to the outside of the ring and sclerenchymatous ground tissue to the inside of the ring. In the larger, complex forms the ring is plicately folded and there may be a centrally-placed hollow in the distal surface. Differences in morphology, in the folding pattern of the rings, in the structure (or absence) of a distal hollow, and in architecture of the major vascular system are employed to delimit genera. Size and shape of the organ, histological features, numbers of sporangia, and presence or absence of lacunae are used to delineate species. Currently recognised genera are Dolerotheca Halle, Sullitheca Stidd et al., Stewartiotheca Eggert and Rothwell, and Bernaultia gen. nov.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1986

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References

Baxter, R. W. 1949. Some pteridosperm stems and fructifications with particular reference to the Medullosae. ANN MISSOURI BOT GARD 36, 287352.CrossRefGoogle Scholar
Dennis, R. L. & Eggert, D. A. 1978. Parasporotheca, gen. nov., and its bearing on the interpretation of the morphology of permineralized medullosan pollen organs. BOT GAZ 139, 117–39.CrossRefGoogle Scholar
Dufek, D. & Stidd, B. M. 1981. The vascular system of Dolerotheca and its phylogenetic significance. AM J BOT 68, 897907.CrossRefGoogle Scholar
Eggert, D. A. & Rothwell, G. W. 1979. Stewartiotheca gen. n. and the nature and origin of complex permineralized medullosan pollen organs. AM J BOT 66, 85–6.CrossRefGoogle Scholar
Galtier, J. & Phillips, T. L. 1977. Morphology and evolution of Botryopteris, a Carboniferous age fern Part 2. Observations on Stephanian species from Grand'Croix, France. PALAEONTOGRAPHICA 164B, 132.Google Scholar
Galtier, J. & Scott, A. C. 1981. Sur la présence de végétaux à structure conservée du Viséen dans le Poudingue Mosaique du Stephanian du Saint-Etienne (France). GEOBIOS 14, 129–31.CrossRefGoogle Scholar
Halle, T. G. 1933. The structure of certain fossil sporebearing organs believed to belong to the pteridosperms. K SVEN VETENSKAPSAKAD HANDL 12, 1103.Google Scholar
Leisman, G. A. & Peters, J. S. 1970. A new pteridosperm male fructification from the Middle Pennsylvanian of Illinois. AM J BOT 57, 867–73.CrossRefGoogle Scholar
Millay, M. A. & Taylor, T. N. 1979. Paleozoic seed fern pollen organs. BOT REV 45, 301–75.CrossRefGoogle Scholar
Phillips, T. L. 1981. Stratigraphic occurrences and vegetational patterns of Pennsylvanian pteridosperms in Euramerican coal swamps. REV PALAEOBOT PALYNOL 32, 526.CrossRefGoogle Scholar
Ramanujam, C. G. K., Rothwell, G. W. & Stewart, W. N. 1974. probable attachment of the Dolerotheca campanulum to a Myeloxylon-Alethopteris type frond. AM J BOT 61, 1057–66.Google Scholar
Renault, B. 1893. Bassin Houiller et Permien d'Autun et d'Epinac. ETUD GITES MINER FRANCE Fascicule IV (Atlas), Ministère des travaux publics, Imprimerie Nationalle, Paris.Google Scholar
Renault, B. 1896. Bassin Houiller et Permien d'Autun et d'Epinac. ETUD GITES MINER FRANCE Fascicule IV (Texte), Ministère des travaux publics, Imprimerie Nationalle, Paris.Google Scholar
Rothwell, G. W., & Eggert, D. A. 1982. What is the vascular architecture of complex medullosan pollen organs? AM J BOT 69, 641–3.CrossRefGoogle Scholar
Rothwell, G. W. & Mickle, J. E. 1982. Rhetinotheca patens n. sp., a medullosan pollen organ from the Upper Pennsylvanian of North America. REV PALAEOBOT PALYNOL 36, 361–74.CrossRefGoogle Scholar
Schopf, J . M. 1948. Pteridosperm male fructifications: American species of Dolerotheca, with notes regarding certain allied forms. J PALEONTOL 22, 681724.Google Scholar
Stidd, B. M. 1978. The synangiate nature of Dolerotheca. AM J BOT 65, 243–5.CrossRefGoogle Scholar
Stidd, B. M. 1981. The current status of the medullosan seed ferns. REV PALAEOBOT PALYNOL 32, 63101.CrossRefGoogle Scholar
Stidd, B. M., Leisman, G. A., & Phillips, T. L. 1977. Sullitheca dactylifera gen. et sp. n.: A new medullosan pollen organ and its evolutionary significance. AM J BOT 64, 9941002.CrossRefGoogle Scholar
Taylor, T. N. 1971. Halletheca reticulatus gen. et sp. n.: a synangiate pteridosperm pollen organ. AM J BOT 58, 300–8.CrossRefGoogle Scholar
Taylor, T. N., & Rothwell, G. W. 1982. Studies of seed fern pollen: Development of the exine in Monoletes (Medullosales). AM J BOT 69, 570–8.CrossRefGoogle Scholar
Warren, A. J. 1955. Structure of the pollen bearing organ of Dolerotheca. Unpublished M.S. thesis. University of Illinois, Urbana.Google Scholar