Insects in Great Britain, 329 
ought severally to help to isolate forms in which these charac- 
ters occur. 
Species : 1. H. alpinum, Linn. Flowers of (a) H. eximium , 
Backh., were carefully observed. On the second and third 
days after the expansion of the head, the pollen was swept 
out in the outer florets; on the fourth day the stigmas of 
these outer florets separated. On the sixth day all the florets 
were open, and the stigmas of the outermost so recurved as 
to be self-pollinated. Thus apparently this form secures self- 
fertilization in the absence of insect visitors. ( b ) H. holoseri- 
ceum , Backh., growing with the last, is perhaps not self- 
pollinated to the same extent. ( c ) H. alpimim , the segregate, 
(d) H. calenduliflorum , Backh., and (e) H. gracilentum , Backh., 
are other Clova forms. 
Species : 2. H. nigrescens, (/) H. Marshallii , Linton, 
(g) H. senescens, Backh., ( h ) H. chrysanthum , Backh., and 
(i) H. lingulatum , Backh., are all forms which we have found 
at Clova. II. chrysanthum is rather distinct in its orange- 
yellow heads, but all the species of insects, seen to visit it, 
were seen on other species, so that so far as we know the 
colour causes no selection. The stigmas become slightly 
revolute, and this brings about self-pollination. 
Species : 3. H. anglicum, Fries, (j) H. angticum , segregate, 
(£) H. iricum , Fries, (/) II. ctovense , Linton, (m) H. cerinthi - 
forme , Backh., were obtained. Also (n) H. callistophyllum, 
F. J. Hanb., has been gathered at Clova. (F. J. Hanbury, 
Brit. Hierac., pp. 65, 66.) On the crags at Loch Brandy grow 
together H. eximium and II ctovense . The former begins to 
flower before the latter, but their flowering-periods overlap. 
Heads of H. ctovense were kept in a room side by side with 
H. eximium , already described. For five days the behaviour 
of H. ctovense was just like that of H. eximium , but on the 
sixth day when the last of the florets of It. eximium were 
open, there were still some florets of H. ctovense to open, and 
further the stigma of H. ctovense never recurved as tightly as 
that of H. eximium , and consequently self-pollination would 
