446 THE ECOLOGY OF PLANTS. 



In highly cultivated countries the hedgerows form one of 

 the most important refuges of the original wild plants which 

 covered the country before the advent of the plough. The 

 other chief refuges are by the sides of streams, in stony waste 

 places, and in permanent pastures. 



419. Field Observations. It cannot be too strongly in- 

 sisted upon that outdoor observations are absolutely essential 

 in studying the distribution of plants and their adaptations 

 to environment. To study this branch of Botany, i.e. Plant 

 Ecology, with success it is necessary to have a good general 

 knowledge of British flowering-plants, which can only be 

 acquired by collecting and identifying, as far as possible, all 

 the plants met with. At first attention may be confined to 

 the commoner plants and to those which show well-marked 

 adaptations to their environment, and which occur chiefly 

 in sharply defined " plant associations," e.g. water-plants, 

 heath-plants, coast-plants. 



The student cannot do better than begin field observations 

 on some definite and fairly uniform area {e.g. a sea-shore ; 

 pond, marsh, river-bank ; heath, common, moor ; meadow, 

 cultivated field or garden with its weeds ; hedgerow, wood or 

 plantation with its trees and undergrowth, etc.). Study this 

 area at all times of the year, identify as many of the plants 

 as possible, and keep a careful record, with sketches, of your 

 observations. The following hints will suggest the main 

 lines on which the inquiry should be conducted ; others will 

 occur as your field-work progresses. 



1. Physical and climatic features of the area under observa- 

 tion (e.g. chemical and physical nature of the soil ; whether re- 

 tentive and ill drained or porous and well drained ; height above 

 sea-level; exposure to, or shelter from, light and wind, etc.). 



2. List of the most abundant plants in the area, with 

 notes (and sketches) on the following points in each case: 

 General habit and mode of life (whether annual, perennial, 

 erect, creeping, climbing, xerophytic, aquatic, saprophytic, 

 parasitic, etc.) ; size, form, texture, etc., of leaves; structure 

 of flowers, with special reference to mode of pollination ; 

 structure of fruits, with special reference to mode of seed- 

 dispersal, quantity of seed produced, etc. 



3. Eeasons why certain species are present in the area 



