6 
Plants suppressed by other plants. 
myrtillus (the dwarf form of the hills in northern England), Poly- 
trichum sp. (without sporangia), Dicranum sp., a few other mosses, 
and Clcidonia rangiferina. More rarely this was the case with 
Nardus stvicta. On Ben Lawers even the predominant, firm and 
rigid Alchemilla alpina was shut up and flattened, where the rosettes 
of J. squarrosus occurred densely (see Plate I, Fig. 2). 
Only in Sphagnum does J J uncus squarrosus seem to succumb. 
I once saw these two together (Crossfell); the Junc.us was sunk 
rather deeply in the wet Sphagnum bed, and this grew freely over 
the leaf points of the rosettes. Consequently the Sphagnum was 
able to shut up the rosettes (as seen in Fig. 1, d), and on account 
of the peculiar consistence and nearly amorphous growth of the 
moss bed, it is not likely that it would be forced back by the spreading 
jfuncus leaves. 
Of herbaceous plants there are indeed very few that constitute 
such an effective biotic factor as J. squarrosus , unless they have 
strong mechanical resources for the struggle against plants of the 
same size. A similar effect we may of course expect in the case of 
woody plants, which in fact very often become predominant in various 
associations other than scrub and woodland. In the British Isles 
there are good examples in Ulex europceus arid U. Gallii on heaths 
and pastures, Vaccinium myrtillus —together with Rubus chamcemorus 
—on the “peat hags” of the Pennines, &c. As regards jfuncus 
squarrosus, there is no doubt that, although it is very much eaten 
by sheep, it will proceed in its conquest of the upland pastures, as 
long as the climatic conditions are favourable. 
Description of the Photographs on Plate I, Illustrating 
Prof. Lindman’s Paper on “ Plants .Suppressed by other Plants.” 
Fig. 1. Yews and Junipers at Kingley Vale, illustrating the suppression 
of Juniper by Yew. Phot. W. B. Crump, 1911. 
Fig. 2. Juncus squarrosus on Ben Lawers: several plants forming a pure 
clump in association of Alchemilla alpina. Phot. J. Massart, 1911. 
