218 Observation of the Origin of Varieties. 
parison of this mutation with those of Ocnothera La- 
marckiana. The two processes have several features in 
common, but possess others which are more or less 
strongly opposed. 
The points of similarity are : the sudden and imme- 
diate origin, the repeated appearance, the mutation- 
coefficient of about 1% (see Vol I, Part II, 14, p. 337), 
the completeness of the new type, and its high degree 
of heritability. 
These common characters justify the description of 
the origin of Linaria mdgaris peloria as a mutation. 1 
But it is a mutation of a special kind. The structural 
change does not extend to all parts of the plant, but is 
confined to the flowers; in their youth the two types 
cannot be distinguished. In the mutations of Oenothera 
Lamarckiana the new characters are analogous to the 
specific characters of related species already existing; 
in the case of Linaria no such analogy exists. On the 
contrary the new character in Linaria occurs as a variety 
in numerous other species, and even in distantly related 
1 LINNAEUS, as is well known, expressed the view that the Peloria 
is a hybrid between the common Linaria vulgaris and some other un- 
known plant. Its comparative sterility favored this view, but as the 
second^of the two parents could not be found this view has since 
been given up. Here, however, I might discuss the possibility that 
L. vulg. hemipcloria might be a cross between L. vulgaris (apeloria) 
and L. vulg. peloria. If this were so the appearance of the latter 
from the former would perhaps have to be regarded not as a muta- 
tion, but as a segregative process in a hybrid race. If this view 
were true the Peloria should first have arisen from the Apeloria, 
without the mediation of the Hemipcloria, a process which has still 
to be observed. It is, however, no more than a pure assumption 
that the hybrid Apeloria 'X Peloria would be a Hemipcloria; in fact 
our knowledge of other cases would lead us to suppose that it would 
be like one of the parents, in this case the Apeloria, and so long as 
there is no direct information on any of these points a further dis- 
cussion of this view seems barren. Moreover it is by no means cer- 
tain that Linaria vulgaris apeloria exists at all, or ever has existed ; 
the variety, in this genus particularly, may well be older than the 
species. 
