MATURE SPOROPHYTE 15 
of the nineteenth century were indeed the heroic age of Plant Morphology, 
and the results then attained will always continue to be the basis of com- 
parison, as applied to the ascending series of green plants. It must, 
however, be remarked that those results were achieved on a purely comparative 
footing, and .at the moment carried no further interpretation with them. 
For these were the ‘days before evolutionary theory held sway in the 
Biological sciences, and accordingly no underlying phylogenetic meaning 
was as yet seen in the facts observed and compared. But eight years 
later Darwin’s Origin of Species was published, and “the Theory of Descent 
had only to accept what genetic morphology had actually brought into 
view.” It is also to be noted that at first no past physiological history 
was traced in the facts of the individual life ; this line of interpretation suffered 
much longer delay, and is even now only gradually becoming apparent. 
As we shall see, however, such a meaning and such a history may still 
be found reflected in those successive phases of the individual life which 
Hofmeister and his predecessors were able to detect and to compare. 
It is along lines such as these that we may best seek for the solution of 
the problem presented by the origin of a Land-Flora. 
It will then be essential for our purpose, in the first place, to follow 
through all its phases the life-history of certain typical organisms, and 
we shall best begin with those which occupy a middle position in our 
system, viz. the Pteridophytes. The common Male Shield Fern (ephrodium 
Filix-mas. Rich.) will serve as a familiar, and also a suitable example. 
This Fern is known to every one as growing in woods and hedgerows, 
and even in more exposed situations, such as the open gills and hill-sides 
of higher-lying districts. It presents a robust appearance, and when fully 
developed it consists of an oblique and massive stock, which is relatively 
short: this is entirely covered over by the bases of the leaves, of which 
the youngest constitute a closely packed terminal bud (Fig. 1). Those 
leaves which are situated further from the apex, and immediately below 
the terminal bud, may in summer be found to be of large size and 
compound structure (Fig. 2); they are of a rather firm texture: individually 
they are in outline not unlike the ancient Greek shield, and collectively 
they form a crown-like series surrounding the terminal bud. Passing again 
further back from the apex of the stock, its surface is found to be closely 
invested by the bases of the numerous leaves of former seasons, the 
upper portions of which, having performed their functions, have rotted 
away. If the plant be dug up, and the soil carefully removed: from it, 
an ample root-system will be seen, consisting of thin, wiry, and dark- 
looking fibrils, which spring fromthe basal parts of the leaves, and may 
bear numerous branch-rootlets. 
All thesé parts consist of tracts of tissue differentiated to subserve 
distinct functions. The Vascular Skeleton, which appears as a cylindrical 
network of strands within the massive axis (Fig. 1, E, F), throws off 
continuous and connected branches, on the one hand into the leaves, 
