Mar. 1911.] BOTANICAL SOCIETY OF EDINBURGH 145 
THE GRASSLAND OF ORKNEY: AN CECOLOGICAL ANALYSIS. 
By G. W. Scartu, M.A. 
Prefatory Note. 
This paper is only part of a systematic cecological study, not yet 
completed, of all the land vegetation of the Orkney Islands, and was 
written with the prospect of forming a part of the complete description. 
It has been suggested to me, however, that, as the cecological classifica- 
tion of Grassland is ina very chaotic state at present, this attempt at 
analysis may contribute a little to its advance, and might lose in value 
by being kept back too long. 
I have therefore decided to publish it separately, but have not greatly 
changed the original wording, as there is still a possibility of its being 
incorporated in the whole work. Some of the references may thus be 
rather unintelligible at present. 
While it is hoped that the main features of the classification adopted 
are fundamental, great accuracy of detail is not claimed, for this is 
really only part of a primary survey of an extensive area, and there 
was no time for soil analysis and other operations of a detailed survey. 
The division grassland is, on the whole, a natural one in 
cecological classification, though its extent and limitations 
are arbitrary. In some regions extensive tracts of natural 
or primitive grass vegetation may occur, but under other 
climatic conditions most of the grassland is of semi-cultural 
origin. 
Grassland may be defined from the other main divisions 
of vegetation by the following characters :— 
1. The soil, as regards moisture conditions, ranges from 
one which is quite dry in summer to a permanently wet 
soil, not, however, so wet as a marsh. 
2. The soil is generally loamy. There is at least no 
distinct formation of peat. The soil may contain a certain 
amount of raw humus and may even overlie a consider- 
able depth of peat, but in the latter case it is safe to 
assume that the peat was formed when some other forma- 
tion occupied the field. 
3. The grasses usually dominate, or plants generally 
associated with the grasses. 
Extensive grassland, either meadow or pasture, is not 
common in Orkney. The climate is too favourable to the 
production of acid humus for these mesophytic types. 
TRANS. BOT. SOC. EDIN. VOL. XXIV. 
