men’’ as a flower, and the so-called filament as the ‘‘flower 
stalk.*” Thus he made comparisons with the Gnetales. 
All of these opinions have been rendered untenable. All 
of the existing gymnosperms have had long ancestries, at 
least into the early Mesozoic. Each group in its own 
manner has been modified or elaborated from simple 
types. It is to these simple types such as Cordaianthus 
that we must make recourse, instead of working back- 
wards from extant forms of uncertain ancestry. 
OTHER CORDAITEAN REMAINS ASSOCIATED WITH THE 
STROBILI. 
It is not my intention to give a detailed description 
of seeds, leaves, or woods, which form conspicuous com- 
ponents of the large Lowa coal ball flora. Three previously 
described types, however, are abundant and, as they pos- 
sibly belong to Mesovylon, brief records of them are in- 
corporated herewith. 
Cordaites (Cordaitophyllum) ef. crassus Grand’ 
Hury. (Figure 21). 
‘There are a large number of cordaitean leaves in the 
lowa coal balls, and these reveal considerable variability, 
so much so, that one is forced to accept the probability 
of the presence of at least several species. The example 
illustrated here is the most abundant. Three morpholo- 
gical characters are noteworthy: (1) the fairly extensive 
development of sclerenchymatous tissue near both the 
upper and lower surfaces of the leaf with much larger 
pointed masses projecting upwards usually, though not 
absolutely consistently, between every two vascular bun- 
dles ; (2) the homogeneity of the parenchyma without the 
development of a palisade tissue near the upper surface ; 
and (3) the small mesarch vascular bundles which are sur- 
rounded by a sheath of tissue of somewhat doubtful 
[12] 
