AN ACCOUNT OF THE BRITISH HIERACIA 181 
demonstrated that the geoesing of nearly-related ‘* species” 
Hieracium does not, as might a@ priori be expected, lead to the 
production of Lge diiate forms, but rather of varieties which 
possess the characteristics of the one or the other parent-forms 
intensified—a result which harmonizes completely with the process 
described by Eimer as one-sided her 
In order rightly to study the hawkweeds of a definite area, it ig 
neumbent on the critical botanist undertaking the difficult task 
that he should acquaint himself with those phenomena of phylo- 
geny and heredity which specially bear on this remarkable genus; 
otherwise he-will attach too much importance to trivial differences 
which are devoid of evolutional significance. Several srggco 
workers have already studied the genus Hieracium in the light of 
such phenomena, and their investigations have been rewarded wi 
success. Himer’s theory of Genepistasis has been applied by both 
f Bri a 
by the investigations of Prof. Ostenfeld, showing the frequency of 
parthenogenesis in Hieracitum—that last shift of an unstable type 
to maintain, at any tie some reputable degree of constancy, even 
if only for one ocean 
It e been interesting had Mr. Linton given some of 
his reasons ne apliting up the British members of Hieracium into 
nd varieties, as the case is not at all parallel to 
that of ‘Aichemilla as studied by German and Swiss botanists, where 
the characters which obtain for the separation of species are of 
quite another category. Further, in the case of a group of plants 
so susceptible to the conditions of environment and of climatic 
variation, the important phenomena outlined in De Vries’s M pose 
a, Species ake a special significance, as further evidenced in Rubus, 
We understand that an observant emerge has noticed that a cake 
ch 
trifling differences in the process of realizing a definite type, when 
certain characters tend to disappear, and others, adjus the 
environment, remain dominant. This factor in the process of 
organic evolution i is pega in a lucid sentence in the author’s 
Introduction :—‘‘ Under the ——- of sf in Seernages con- 
ae oe ng Sieinie tendency to variation become 
g a variety to specific aban is Donate done in 
this eaeiaiais}s and in transferring a variety from one species to 
another, the name of the original authority in the new combination 
should be changed, otherwise it Candollean 
rule in that it makes an author say ‘what he has not said. There 
seems rather a bE caps? throughout to take . d the 
opinions of certain Scandinavian botanists on dried specimens sent 
