I. On the structure and affinities of fossil plants from the palæozoic rocks.—On cheirostrobus, a new type of fossil cone from the lower carboniferous strata (calciferous sandstone series)
The higher Cryptogamic Flora of the Palæozoic period was exceedingly rich compared with that of our own day. Confining our attention to those Cryptogams in which the fructification has the form of a definite cone or strobilus, we find that at least eight distinct types of such strobili are already known from the primary rocks, leaving out of account all minor differences of a merely specific value, and ignoring imperfectly-known forms. From the recent Flora we could not obtain more than three equally distinct classes of Cryptogamic cones. The fossil strobili at present discovered group themselves under three categories,— the Lycopodiaceous, the Equisetaceous or Calamarian, and the Sphenophyllaceous The two former coincide with well-known recent orders, while the last belong to a purely fossil group, at present only known from the Palæozoic formations, and so far of undetermined affinities.