On Porostrobus zeilleri Nathorst and its spores with remarks on the systematic position of P. bennholdi Bode and the phylogeny of Densosporites Berry

D.C. Bharadwaj

doi:10.54991/jop.1958.571

Authors

D.C. Bharadwaj Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow 226007, India

DOI:

https://doi.org/10.54991/jop.1958.571

Abstract

This paper contains results of a reinvestigation of Porostrobus zeilleri Nathorst., a fructification from the Lower Carboniferous of Spitzbergen and, based thereupon, remarks on the systematic position of P. bennholdi Bode and the phylogeny of Densosporites Berry.

The cone studied represents the lower portion including a part of the stalk. The cone shows rhomboid sporangia arranged spirally, sporangial sporophylls not visible but fine delicate hairs, apparently sporophyllends, seen on the matrix along one of the sides of the cone. Megasporat and microsporate sporangia occur intermixed. Megaspores are sack-like, bottom heavy and gulate or vestibuled with verrucose ornamentation of the exine. Microspores are cingulate, roundly triangular with spinose ornamentation. Inner body has 3 inter-ray papillae.

Porostrobus shows lepidodendroid as well as sigillarioid characters.

Porostorbus bennholdi Bode is shown not to be a Porostrobus at all. It is provisionally referred to Lepidocarpon.

The microspores of Porostrobus agree morphographically as well as stratigraphically to the genotype of the dispersed spore genus Densosporites Berry. In view of the fact that Densosporites also occurs in strata where Porostrobus has never been found, it is postulated that presently circumscribed Densosporites contains spores of cone genera other the Porostrobus as well.

PS. Porostrobus is considered distinct from Selaginellites and S. canonbiensis Chaloner is advised inclusion in Bothrostrobus (Nath.) Sew.

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References

BERRY, W. (1937). Spores from Pennington coal, Rhea country, Tennessee. Amer. Midl. Nat. 18: 155-160.

BHARDWAJ, D. C. (1955). The Spore genera from Upper Carboniferous coals of the Saar and their value in stratigraphical studies. The Palaeobtonaist, 4: 119-149.

BHARDWAJ, D. C. & VENKATACHALA, B. S. (1958). Microfloristic evidence on the boundary between the Carboniferous and Permian Systems. The Palaeobotanist. 6: 1-11. https://doi.org/10.54991/jop.1957.546

BODE, H. (1929). Zur Kenntnis der Gattung Porodendron Nathorst (non Zalessky). Palaeontogr. 62: 125-139.

CHALONER, W. G. (1953). On the Megaspores of four species of Lepidostrobus. Ann. Bot. 17: 263-293.

Idem (1953a). A new species of Lepidostrobus containing unusual spores. Geol. Mag. 90: 97-110.

Idem (1953b). On the megaspores of Sigillaria. Ann & Mag. Nat. Hist. 6: 881-897.

CHALONER, W. G. (1954). Notes on the spores of two British Carboniferous Lycopods. Ann. & Mag. Nat. Hist. 7: 81-91.

Idem (1958a). Polysporia mirabilis Newberry, a fossil Lycopod cone. J. Palaeontol. 32: 199-209.

Idem (1958b). A Carboniferous Selanginellites with Densosporites Microspores. Palaenontology 1: 245-253

DARRAH, W. C. (1938). A remarkable fossil Selaginella with preserved female gametophyes. Bot. Mus. Leafl. Harv. 6: 113-136.

DIJKSTRA, S. J. & VIERSSEN TRIP, P. H. VON. (1946). Eine monographische Bearbeitung der Karbonischen Megasporen mit besonderer Berucksichtigung von Sudlimburg (Niederlande). Med. Geol. Sticht. 103: 1-101.

HALLE, T. G. (1907). Einige krautartige Lycopodiaccen palaeozoischen und mesozoischen Alters. Ark. Bot. 7: 1-17.

HOLDEN, H. S. (1932). Variations in Megaspore numbers in bothrodendron mundum. New Phytol. 31: 265-269.

HOSKINS, J. H. & ABBOTT, M. L. (1956). Selaginellites crassicincuts, a new Species from Desmoinesian series of Kansas. Amer. J. Bot. 43: 36-46.

LUNDBLAD, B. (1950). On a fossil Selaginella from the Rhaetic of Hyllinge, Scania. Sven. Bot. Tidskr. 44: 477-487.

NATHORST, A. G. (1894). Zur palaeozoischen Flora der arktischen zone. Koni. Svenska Vetensk. Akad. Handl. 26: 5-80.

Idem (1914). Nachtrage zur palaeozoischen Flora Spitzbergens. 1-110 Stockholm.

POTONIE, R. & KREMP, G. (1956). Die Sporae dispersae des Ruhrkarbons usw. Teil III. Palaeontogr. 100B: 65-121.

SCHOPF, J. M. (1941). Contributions to Pennsylvanian Palaeobotany. Mazocarpon oedipternum sp. Nov. and Sigillarian relationships. III. Geol. Surv. Rept. Inv. 75: 1-53.

SEWARD, A. C. (1910). Fossil Plants II. Cambridge.

WATSON, D. M. S. (1908). The cone of Bothrodendron mundum. Mem. Manchr. Lit. Phil. Soc. 52: 1-15.

ZEILLER, R. (1906). Bassin houiller et Permian de Blanzy et du Creusot, Fasc. 2, Etud. Gites min. Fr. 1-261.