K.— BOTANY. 175 
not to go far beyond our facts, and, in particular, to avoid elaborate 
derivations of one type of structure from another where the supposed 
transitional forms have but a purely subjective existence; we have 
realised the difficulty of tracing homologies. We may still be allowed to 
seek affinities, even where we cannot trace descent. And though we 
may sometimes go a little beyond our tether and give rein to bolder 
speculations, there is no harm done so long as we know what we are 
doing, and there may be even some good in such flights if our scientific 
use of the imagination serves to give life to the dry bones of bare 
description. On this subject I am somewhat more optimistic than 
Dr. Lotsy, who, abandoning his ‘ Stammesgeschichte ’ point of view, 
has dismissed all attempts at phylogenetic reconstruction as ‘ fantastic.’ 
There are some questions of the highest interest that at present can 
scarcely be approached in any other but a speculative way. Within 
the last year or two new points of view have thus been opened out. 
For example, Dr. Church’s able essay on ‘ Thalassiophyta and the 
sub-aerial transmigration’ has brought vividly before us the great 
change from marine to terrestrial life. 
The origin of a Land Flora had, of course, been discussed with 
much ability before, but rather as incidental to a morphological theory. 
Dr. Church puts the actual conquest of the land in the foreground. We 
watch the land slowly rising toward the surface of the primeval ocean, 
the rooted sea-weeds succeeding the free-swimming plankton, and then 
the continents slowly emerging and the drama of the transmigration 
as the plants of the rock-pools and shallows fit themselves step by step 
for sub-aerial life when the dry land appears. It is a striking picture 
that is thus displayed to our view—whether in all respects a faithful 
one is another question; we must not expect impossibilities. |The 
_ doubts which have been raised relate first to the assumed world-wide 
ocean, which seems not to be generally accepted by geologists. If con- 
_tinental ridges existed from the first (i.e. from the original condensa- 
tion of watery vapour to form seas), the colonisation of the land may 
have followed other lines and have happened repeatedly. Perhaps, 
after all, that would not greatly affect the botanical aspects of the 
transmigration. 
The other difficulty is, however, a botanical one. Dr. Church looks 
at the whole problem from the sea-weed point of view, and it is well he 
does, for sea-weeds have been badly neglected, especially by some of the 
great continental morphologists, who used to lead our speculative 
flights. Dr. Church is much impressed by the high organisation of 
many sea-weeds, especially, in the living marine flora, by that of the 
Brown Alge. Here we find well-differentiated leaves, special repro- 
ductive shoots, extremely efficient holdfast roots, and, sometimes, a 
definite alternation of generations, while, on the anatomical side, we 
meet with true parenchymatous tissues, a well-developed phloém and 
secondary growth in thickness. There is, in fact, in many respects, 
an anticipation of, or an analogy with important features which charac- 
terise the higher plants of the land. 
Dr. Church believes that the chief morphological characters of the 
Land Flora were first outlined in the sea; that such characters were not 
