The spores of Lycopodium, Phylloglossum, Selaginella and Isoetes and their value in the study of microfossils of Palaeozoic age

The LYCOPODIINAE are a ubiquitous race of plants: members are found in many different parts of the world from the tropics to the polar regions, and tinder a great variety of habitat conditions.

The families with living representatives afford ample evidence of antiquity; and their fossil relatives indicate the abundance of the group during Palaeozoic times. The coals of the Carboniferous Age are to a large extent composed of the carbonised remains of these plants; their spores are found in vast numbers in most coal seams.

The study of fossil spores within the last 25 years has led to their being used as an aid in the correlation of coal seams. Up to the present, the classification of fossil spores has been an arbitrary one; with the increasing use of spores as zonal indices in coalfield work, a more scientific system of nomenclature has been found necessary. A binomial system has been promulgated in America which in all probability will form the basis of future work on classification. Although a general review of the spores of modern Pteridophyta has already been published by the author (Knox, 1938), the lack of any comprehensive survey of the spore morphology of living species of Vascular Cryptogams has proved a considerable handicap in framing a classification of fossil spores; the present study of the spores of modern species of the LYCOPODIINAE has been undertaken with a view to gaining more exact knowledge of spore morphology in this large and important group, both generic and specific, in order to make possible an assessment of relative values for purposes of palaeobotanical taxonomy.

The basis of the following work is furnished by a detailed account of the morphology of the spores of Lycopodium, Phylloglossum, Selaginella and Isoetes, derived from as many of the living species as it has been possible to obtain samples.