INTRODUCTION. 
Or the. two branches of the Organic World, the Vegetable Kingdom 
might be expected to present a simpler problem of Descent than the 
Animal Kingdom, on account of the prevalent non-motility of the mature. 
individual. That fixity of position which the Higher Plants show, should 
tend to a.more obvious record of previous events than the ambulatory 
habit of Animals, and especially of their higher types, would seem to 
allow. It is reasonable to expect that organisms of fixed position 
should demonstrate in their distribution some traces of their past history ; 
these would be specially valuable in the elucidation of the problem of 
the Origin of a Land Flora, and of the relation of the Land-growing 
Plants to those of the water. 
But this prima facée. probability is largely discounted by the extra- 
ordinary facility shown by Plants for the distribution of their germs. A 
comparison of the Higher Animals with the Higher Plants in respect 
of motility shows that the motile parent in the former is without special 
provision for distribution of its germs, while the Plant with its fixity of 
station shows high elaboration and variety in the methods of their 
dissemination. In consequence of this there will be a natural tendency 
in the vegetable kingdom, as there is also in that of animals, towards 
the obliteration of any such genetic record as the fixity of position of 
the individual plant during its active vegetation might otherwise have 
been expected to have left. Accordingly, on examination of the vegetation 
of any ordinary country-side, its uplands and lower levels, its swamps, 
streams, and pools, plants of the most varied affinity are found to be 
promiscuously shuffled together, and show little sign of ranking in their 
position according to their descent. For instance, the Flora of still 
fresh waters may be found to consist of such plants as various green 
Algae and Characeae ; of /soetes and Piludaria ; together with Angiosperms, 
such as Littorella, Lobelia, and Subularia. In flowing mountain streams, 
in addition to green Algae may be found Chantransia and Lemanea; 
associated with Fontinal’s and sundry Angiosperms. Conversely, in various 
positions on land, along with certain Algae in moist spots, representatives 
A 
