ECOLOGY OF WOODLAND PLANTS. 335 
Some of the observations contained in this paper were 
communicated to Section K (Botany) at the Southport Meeting 
of the British Association in 1903, and further results communi- 
cated to that Section at the Cambridge Meeting in 1904. 
A prolonged absence from England has occasioned delay in 
the publieation of this paper. Since its completion several 
important contributions have appeared or have come to my 
notice, and I have taken the opportunity to include references 
to many of them. In this connection I wish to thank Prof. 
Hans Schinz of the University of Zürich, and Prof. C. Schröter 
of the Polytechnieum, Zürich, for their kindness in granting me 
permission to use the excellent libraries connected with these 
and other institutions. 
Ecoroax rw BRITAIN. 
In 1836 Hewitt Cottrell Watson contributed a short paper (98) 
to a discussion, initiated by R. B. Hinds (48) the previous year, 
on the construction of Maps illustrating the distribution of 
plants. The ideas in the minds of botanists at the time were 
concerned chiefly with mapping species. Watson’s knowledge 
of the distribution of plants, however, led him to see that two 
methods were possible. Not only could the distribution of 
species be thus indicated, but maps of a very different type 
could be produced which would indicate vegetation. Although 
thisidea was in Watson's mind, it was eventually erowded out in 
a statistical study of the distribution of species (100). 
The present study of Plant Associations and Ecology in 
Britain, as elsewhere, has been based upon and greatly influenced 
by the admirable work of Warming (102), about which it is 
impossible to speak too highly. The works of other Continental 
botanists have also had a marked effect, especially those of 
Beck (4), Drude (25), Flahault (29), Graebner (36), Kerner (52), 
Schróter (84), and Schimper (33). Running close upon these 
are the researches of American Ecologists, who have recently 
shown great activity in this direction; and the publications 
of Pound and Clements (79), Cowles (18), Harshberger (44), 
Ganong (33), MacMillan (63), and others have taken a permanent 
place amongst the contributions to this subject. For a more 
extended bibliography a recent paper by Clements (14), also his 
excellent ‘Research Methods in Ecology’ (15), may be usefully 
consulted, as well as numerous papers during recent years in 
the * Botanical Gazette.’ Although these deal often with areas 
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