704 TRANSACTIONS OF SECTION K. 
To compare the structure of organisms with each other is, of course, the 
recognised method of comparative anatomy, of systematic botany, and, in fact, 
of all branches of morphology. The great difficulty in all such work is to 
distinguish between adaptive characters of comparatively recent origin and the 
characters inherited from remote ancestors. The history of systematic botany 
is very instructive in this respect. Systematists discovered by degrees, and by 
means of repeated failures, that characters could not be picked out as important 
for purposes of classification on @ priori grounds. No character is of uniform 
importance throughout vascular plants, for example. On the contrary, it may 
be of great value in the classification of one group and worthless in another, 
though closely allied. Generations of botanists have laboured to build up the 
Natural System in its present form, and it is constructed from the ruins of 
abandoned systems. We all agree now that the guiding principle in all mor- 
phology is that our classification should represent relationships founded on 
descent only. But the Natural System was complete in its main features before 
that principle was understood. It represented the feeling for real affinity 
developed in botanists by the study of plant form, independently of any theory 
as to the cause of such affinity. 
This, of course, is the commonplace of botanical history, but we do not 
always realise that all morphological work is done under similar conditions. 
The only valid appeal from criticism is to the future : a new method is approved 
by its results. Therefore, to embark on a new branch of morphology is a real 
adventure. The morphologist risks much time and much labour. He knows 
that the evidence which he proposes to gather painfully, to test critically, to 
present logically, may, after all, prove of little consequence, and he has to 
depend on his own instinct to lead him in the right course. In his degree he 
resembles Columbus, to whom a few sea-borne seeds and nuts meant a new 
continent. 
Hence the difficulty of criticising recent work. When once a conclusion of 
some importance has been formulated it may be tested by evidence drawn from 
other branches of research. Until that time criticism from outside is of little 
value. Those who are working at the subject must, of course, form their own 
opinion on its possibilities, for each has to decide for himself whether he shall 
continue on those lines. 
The subject of seedling anatomy is no longer very new. It is too late now to 
debate on the a priori probability of ancestral characters surviving in the young 
seedling. No one doubts that a vascular stump sometimes persists after the 
organ it originally supplied has disappeared.’* Therefore there is no glaring 
improbability in the suggestion that the vascular skeleton of the young seedling 
may afford a clue to the structure of a remote ancestor. But this is only saying 
in other words that botanists are justified in giving the subject a fair trial. That 
trial is now proceeding. Some general conclusions have been formulated already, 
but they have not yet stood the test of time. In all probability the final judg- 
ment on this subject will be given by a future generation of botanists on evidence 
not as yet before us. In the meantime we shall all form our own opinion as to 
similar nature has been done lately on Gymnospermous seedlings that I add a list of 
the principal papers :— 
Dorety, Helen A. Vascular Anatomy of the Seedling of Microcycas calocoma. Bot. 
Gaz., Xtvu., p. 139, 1909. 
Hill, T. G., and de Fraine, Ethel. The Seedling Structure of Gymnosperms. I., Ann. 
Bot., Xxu., p. 689, 1908. II., id. xxmz., p. 189, 1909. III., cd. xxm., p. 433, 1909. 
IV., id. Xxtv., p. 319, 1910. 
Matte, H. L’appareil libéroligneux des Cycadies. Caen, 1904. 
Shaw, F. J. F. The Seedling Structure of Araucaria Bidwillii. Ann. Bot., Xxut., 
p- 321, 1909. 
Sykes, M. A. The Anatomy of Welwitschia mirabilis. . ... Trans. Linn. Soc., 2. 
Bot. vii., p. 327, 1910. 
Thiessen, Reinhardt. The Vascular Anatomy of the Seedling of Dioon edule. Bot. 
Gaz., XLVI., p. 357, 1908. 
12 Cf. the discussion of the homology of the Orchis-flower in Ch. Darwin’s 
Fertilisation of Orchids, chap. xiii., p. 235 in second ed., 1888. 
4 ghotgan dk 
