Die Euphrasia-Arten Norwegens. 319 
strip found along the river side near the sea-shore, just suf- 
ficiently elevated to be dry when the water is at its normal 
level. Thus I observed, for instance, well developed forms in 
wet localities, with distinctly smaller and less protruding corollas 
than those of the typical form, much less hairy to almost bare, 
with leaves, differing from those of the typical form in just the 
same way as those of the singular variety just mentioned. This 
latter has been discovered by Swedish botanists and mentioned 
by them as E. bottnica Kihlm. (= E. micrantha Brenn. = E. 
hebecalyx Brenn.), which also was the reason why I examined 
this form thoroughly. The true E. bottnica —- which I, how- 
ever, only know from herbaria — has, at any rate generally 
Speaking, a different appearance, but answers on the whole in 
its different characters very well to the Norwegian form. I should 
therefore suppose that the peeuliar Baltic species (E. bottnica), 
which was considered to take an isolated position within the 
genus, in reality has derived from the surrounding E. latifolia, 
probably in long past times, in a similar manner to our Nor- 
wegian form. (Also Kihlmann seems originally to have been 
of a similar opinion, having regarded the ,isolated“ species as a 
mere variety, whilst he later on seems to have modified his 
view.) 
The species accepted by Wettstein represent more or less 
natural series of the primary forms. Some of them are tolerably 
well defined, whilst others pass into each other without percept- 
ible limits. Even in the better defined species intermediate forms 
are generally more or less frequent, apparently being partly hy- 
brids, partly variations. Hybrids between the closely allied pri- 
mary forms may be supposed to be very frequent, but also be- 
tween the species accepted by Wettstein hybridization seems 
to be quite a common phenomenon, though usually rather dif- 
ficult to detect or prove. Here the more ,definite" characters, 
which, however, in most cases are merely artificial (as for in- 
stance glandular hairs) will help to point out the hybrid, and by 
means of such and similar distinguishing marks hybrids even be- 
tween the relatively most distant species will be really found to 
occur and by no means seldom. Å striking exception to this 
rule is our single species of Wettstein’s group Angustifoliæ, 
which seems to be less adapted for crossing with the other 
species, though also here hybrids (with E. latifolia) occur. If 
