Woodhead : Notes on the Bluebell. 



87 



bell is dense, and where it thins out. In the vertical section of 

 the soil in the dense area we find that the loose leaf mould on 

 the surface is occupied by the rhizomes of Holcus viollis ; they 

 are practically confined to this layer, sending- out fibrous roots 

 from their nodes, which penetrate to some extent the upper part 

 of the peaty humus. This humus may be called the bracken 

 layer, for in it the rhizomes of this fern ramify, often keeping- to 

 the junction between it and the yellow loam below into which 

 many of its root fibres grow. Young bulbs of the bluebell may 

 be seen in this layer on their way downwards. Their final home, 

 however, is in the firm loam. 



These three plants, Holcus mollis, bracken, and bluebell, 

 practically constitute the flora of the undergrowth in this area, 

 other species being quite subordinate. Superficially they may 

 be thought to be in severe competition with each other, each 

 striving for mastery over its neighbour. Such, we see, is not 

 the case, we have instead a little association of species livings in 

 concord. Their soil requirements, their modes of life, their 

 periods of active vegetative growth, their times of flowering and 

 fruiting are all difl"erent. In many respects, therefore, each 

 species is not within the sphere of influence of the other, and 

 they flourish apace. Competition, such as it is, goes On between 

 individuals of the same species. 



The trees, as we have seen, are chiefly oak, and as the blue- 

 bell is up early, drawing upon the rich store of food reserves i.i 

 the bulb, its foliage leaves are well advanced before the oak is in 

 leaf, and therefore suff"ers little from overshadowing. When the 

 bracken fronds unfold, their deep shade together with the shade 

 of the trees in leaf, affects to some extent the late assimilatory 

 activity, and so acts as a competitor. 



Let us now consider the conditions in the area where the 

 bluebell thins out and ultimately disappears. In comparing this 

 area with the distribution of the trees, w^e see it is not entirely 

 a question of light, as its distribution is not co-extensive with 

 the oak area, that is, with trees with an open canopy. We find 

 that several factors are concerned. An examination of the soil 

 and plants in the thin area, of which Fig. 12 is a diagrammatic 

 section, presents rather interesting features. There is little or 

 no leaf mould or humus, and the soil for the greater part is 

 a stiff sticky clay. In this area occur among- other species 

 yellow dead-nettle, dog's mercury, and arum, and though some of 

 the rhizomes lie near the loose material above, their long fibrous 

 roots grow deeply into the soil. Here, too, are numerous root 



1904 March i. 



