The Genus Sphenophyllum. 215 
tween the emerged, the partially submerged and deeply submerged 
leaves. Usually the descriptions have been based upon fragments 
and it will only be when larger specimens, showing more of the 
plant, are compared that the synonymy will be cleared up. I have 
received from American localities what I have regarded as repre- 
sentatives of the following species. . 
1. Sphenophyllum Schlotheimi, Brgt. This is the most widespread 
and abundant species in the Coal Measures of North America as 
well as Europe. It does not occur in the flora of the lowest coal 
in the Mississippi valley, but begins midway of the lower coal group 
and runs through the upper productive Coal Measures. 
2. Sphenophyllum erosum, \..& H. This is common in the flora 
of the lower coal, quite rare above; sometimes the leaves are much 
larger than those represented on figure 1 of our plate. They are 
broad wedge-shaped, normally six in a whorl, with strong and 
nearly uniform teeth across the straight truncated edge of the end 
of the leaf. As they descend on the stem they become laciniate 
by the splitting of the extremity of the leaf into two lobes, each 
of which is bi-furcate. This is the variety Saxzfragacfolium of 
European authors. It may include S. zfurcatum, Lx., as suggested 
by Schimper, but I have from the lower coal of northern Ohio 
what seems to be the Arkansaw plant and which is characterized 
by a long-jointed, deeply-fluted stem quite unlike that of the nor- 
mal form of S. evosum. 
3. Sphenophyllum filiculmis, Lx. This beautiful species I have 
from the upper Coal Measures of Ohio, Pennsylvania and Rhode 
Island. It is not always slender-stemmed as the name would indi- 
cate, but may be recognized by its narrow strap-shaped toothed 
leaves of which two are deflected and are very short. 
4. Sphenophyllum oblongifolium, Germar. This occurs sparingly 
in Ohio and Pennsylvania, but is the most common species in 
Missouri and Kansas. ‘The length of the leaves varies somewhat, 
but is generally from one-quarter to one-third of an inch; the out- 
line is oblong, narrowed to the base, the summit bifid and toothed. 
5. Sphenophyllum angustifoium, Germ. Of this species the 
leaves are from one-half to five-eighths of an inch long; narrow, 
laciniate at the summit with acute teeth; generally six in a whorl, 
sometimes twelve; not uncommon at Talmadge and Youngstown, 
Ohio, in the roof shale of coal No. 1. 
6. Sphenophyllum longifolium, Germ. ‘This is a large species of 
