MEMBERS OF THE PLANT BODY 325 
guise and exhibit their true nature.! The proof of a theory is 
in the using; for the present it will be enough for us to have 
gotten a preliminary idea of what the segment theory means 
when applied to our typical plant. 
Other questions, closely connected with the foregoing one, 
are, What members may a segment have? and, How may 
these be distinguished under all their disguises? The flax 
embryo, as we have seen, represents a segment reduced to 
about its simplest terms. We here recognize an axial member 
bearing lateral members,—the stem-part and the leaf-part,— 
one implying the other. When the root-part appears we have 
another member which is also axial, but differs from the 
stem in being without leaves. As the root elongates there 
appear near its tip numerous hair-like projections which 
differ essentially from leaves in being merely superficial 
outgrowths not continuous with the innermost parts as is 
the case with leaves. Superficial appendages of this sort 
often occur in other plants on the stem and leaves as well 
as on the root. Such more or less hair-like outgrowths are 
best regarded as parts of members rather than as members. 
In the essential organs of the flower we meet with a difficulty 
regarding the real nature of the pollen-sacs and ovules or 
egg-sacs as we may call them. In the flax they both might 
be taken to be parts of the peculiar leaves which we regard 
as forming the stamens and pistil. But there are other plants, 
as we shall see, in which an ovule appears on the very tip 
of the stem or axis, while in some cases pollen-sacs seem to 
grow directly from the stem. We can then hardly call such 
organs parts of a leaf. On this account and for other reasons 
1 The theory of floral structure which likens a flower to a leaf-rosette 
originated with the poet Goethe to whom it was suggested by seeing 
a green rose such as occasionally appears in gardens. This theory has 
proved to be a helpful means of understanding the relation of the various 
parts of plants to the fundamental plan of structure; but as it tells 
only part of the truth it has been somewhat misleading, and it requires 
to be modified considerably from its original form to be in accord 
with more recent views of vegetable morphology. As developed above, 
however, it is believed that the theory will be found to avoid the un- 
warranted assumptions which have brought into it discredit, and to re- 
tain the features which have made it useful, while at the same time 
such modifications are made as will render it a valuable means of con- 
veying modern views. 
