Stapledon.—On the Plant Communities of Farm Land . 177 
(e) Species, although abundant in a district which, are quite exceptional 
under even the poorest £ take \ 
Spergula arvensis .* Legousia hybrid a, 
Sonchus arvensis. Chenopodiiim album.* 
Chrysanthemum segetum .* 
* The seeds of species thus marked in the above lists are all more or less plentiful in poor seed 
mixtures. 
It appears from a consideration of the above lists that except for 
Cnicus lanceolatus , which is perhaps a typical weed of both young leys and 
older grass-land, the only plants met with under * seeds ’ that do not occur 
elsewhere in the rotation are certain exotics 1 introduced with the clover 
seeds and which can grow under grass-land conditions. 
If the plants mentioned under headings (b) and (c) are regarded as 
being characteristic weeds in ‘ seeds ’ on soils that suit them, it would seem 
that the following growth forms are well adapted to compete with the sown 
turf-forming and gregarious species. 
A. Plants which produce Seedlings capable of attaching themselves 
closely to the ground. 
( a ) Annuals. 
The most successful annuals are those which either in the first or second 
generation form little cushions on the ground (they appear thus in the late 
autumn) ; these autumnal plants do not, however, flower till the following 
spring — that is to say, they are, under the conditions obtaining, hibernal 
annuals. Good examples are : Viola tricolor (agg.) (often from second 
generation), Alchemilla arvensis (usually first generation), Trifolium minus 
(first or second generation), and Myosotis arvensis (usually first generation). 
Even more successful are those definitely hibernal annuals which form 
strong rosettes on the ground during the first autumn, e.g. Geranium rnolle 
and G. dissectum, and Er odium cicutarium (this plant often becomes a 
biennial or even a short-lived perennial). 
(b) Biennials and Perennials. 
The most successful are plants which during the first autumn produce 
considerable cushions, mats, or rosettes close on the ground, and subse- 
quently develop a spreading or creeping manner of growth, or send up 
comparatively long flowering stems. Examples of the first type are 
Ranunculus repens, Beilis perennis, Chrysanthemum leucanthemum , Veronica 
serpyllifolia (shortly creeping), Prunella vulgaris, and Rumex Aceto sella ; and 
of the second, Cnicus lanceolatus, Hypochoer is radio ata , Taraxacum officinale , 
* Exotic to the particular district. 
