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
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.