214 Cincinnati Society of Natural Fitstory. 
The fructification of Sphenophyllum is shown in many fruit 
spikes associated with the leaves and stems just described and 
supported on stems like figure 4. These fruit spikes are when 
complete eight inches or more in length; when immature they are 
invested with leaf-like bracts which are prolonged above into a 
brush-like summit.. The bracts seem to have been deciduous, for 
we find many specimens like figure 7 from which they have 
disappeared and the surface is occupied by numerous approximated 
whorls, each composed of a large number of closely set obtuse 
scales, (sporangia?) within or behind which are spores. 
The question of the botanical relations of Sphenophyllum has 
been much discussed. Brogniart early suggested that it was allied 
to Marsila, but in his Tableau des Genres, (1849) p. 53, he 
places it with Annularia and Asterophyllites in a special family 
between the Marsiliaceze and Equisetacez. 
Lindley and Hutton, (Fossil Flora, Vol. I, p. 43,) compare 
Sphenophyllum witn the Coniferze and specially with Salsburia, 
but Brogniart has clearly shown that there is quite as little resem- 
blance with the Coniferz as with the Marsiliacez. ‘The verticil- 
late arrangement of the leaves is a character common in Marsilia, 
and but rare in the Conifer, and the number of leaves ina whorl 
never exceeds three; also the whole habit of the plant was differ- 
ent from that of any conifer known. It was small, spreading, 
herbaceous or frutescent, having very little wood tissue and was 
aquatic in habit. In its jointed and striated stem, the pronounced 
verticillate arrangement of the leaves, and in its fructification, 
Sphenophyllum has a much stronger resemblance to the Equisetaceze 
than to either the Marsiliacezee or Conifere. The fruit spikes 
have also much the same structure as those of the Lycopodiacez, 
though the vegetative organs, as well as the general habit, were 
very different. 
Taking all the evidence into account, we are compelled to re- 
gard Sphenophyllum as representing a peculiar and extinct family 
of plants that flourished in all parts of the world during the Devo- 
nian and Carboniferous ages. They disappeared at the close of 
the Permian and have no nearer relative in our living flora than 
Liquisetum. 
While the genus Sphenophyllum is so distinctly defined, about the 
species there is much confusion. ‘This is due partially to the in- 
herent variability of the plant, but more from the difference be- 
