The Ecology of Calluna vulgaris. 61 
(6). Pot cultures were started using seed and fresh soils from the 
field, with a view to detailed observations on the behaviour of seeds 
and seedings under experimental soil conditions. Full analyses of 
the soils are available and have been recorded in a previous paper 
(loc. cit.). In these analyses the soils are referred to as “heather 
area” and “soil over chalk” respectively. For the sake of brevity 
they will be known as “heather” soil and “chalk” soil in the 
present paper. The former is apparently a good fertile loam 
although the percentage of calcium carbonate is low : the latter is 
a typical chalk-down soil containing 4P8% calcium carbonate. 
It is convenient to deal with the results of these cultures under 
two heads:—(A) Germination, (B) Growth. 
A. Germination. Seed was collected in the capsules during 
October, dried in the laboratory at air temperature and stored in 
paper bags. When required it was rubbed down, sieved, and the 
seed picked out by hand. 
The seed is very small, with a rough testa, abundant oily 
endosperm and a minute straight embryo. Sowings were made in 
pots of fresh soil, under glass, using approximately the same number 
of seeds per pot, and records kept of the rate of germination, the 
number of seedlings, and the growth and condition of the roots and 
shoots at successive stages. 
In the autumn, germination begins 25—30 days after sowing, 
and is usually rather slow and irregular. In the spring it takes 
place more uniformly, 16—19 days after sowing. 
In “ heather” soil, seeds germinate at the same rate and exhibit 
about the same germination capacity as on blotting paper in a 
germinator. As compared with this, the rate of germination is 
greatly retarded and the germination capacity markedly lowered in 
the “chalk” soil. A majority of the seeds do not germinate. 
Germination of the remainder is delayed—seedlings first appearing 
after two or three months and then in very small numbers. Seeds 
continue to germinate irregularly for six months or longer, but the 
total germination capacity is extremely low as compared with the 
controls. 
In order to compare the behaviour of Calluna seed in this 
respect with that of other plants, sowings were made, in the two 
soils, of Foxglove (Digitalis purpurea) as a representative calcifuge, 
and of Kidney Vetch (Antliyllis vulneraria ) as a calcicole. The 
latter plant is abundant on the down soil in the field. 
In each case germination is simultaneous and the germination 
capacity similar in the two soils. 
