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218 GOTE TURESSON 
sections of leaves from these cultivated plants show much the same 
structure (both forms having one layer of palisades), but the cuticle 
of the upper epidermis is found to be thicker throughout in the cul- 
tures of the pasture plant than in those of the plant from the woods. 
Repeated measurements have given a mean value of 7,8 4 for the 
former and 5,6 x. for the latter. The outer wall of the lower epider- 
mis is also thicker in the former than in the latter, especially in places 
below the vascular bundles, where it attains a considerable thickness 
and becomes much folded. Thus the results of the cultivations point 
strongly to the assumption that there’ are in Sweden at least two 
hereditary types of this species, the one growing in meadows and 
pastures, the other in the woods. The differences in the leaves show 
that the latter is manifestly a shade plant as compared with the former. - 
DAHLGREN (1922 a) has recently traced the distribution of L. 
nummularia in Sweden and pointed out that the plant has to a large 
extent been spread by human agency. It remains to be settled 
whether the above described shade type from the woods is native 
in our country, while the type from the meadows and pastures is 
introduced and spread through man, a view, which might. be an 
approximation to the truth. A further point of interest will be affor- 
ded by the crossing-experiments between the two types to be started 
a following year. The experiments made by DAHLGREN (1922 b) have 
shown that plants from widely different parts in Sweden are sterile 
when crossed with each other, while fruit develops when Swedish 
plants are crossed with German and Austrian specimens. It seems 
reasonable to assume that the failure in the case of the crossings 
where Swedish material was exclusively used was due to the fact 
that the plants were members of the same clone, in this case probably 
the pasture nummularia, as this type has no doubt the largest distri- 
bution in the country. 
It should perhaps be said that the shade variety of L. nummularia, 
discussed above, has not been found described in the literature. DoMIN 
(1904), who lists a number of forms of the species, does not mention 
any such form. 
C. DACTYLIS GLOMERATA. 
A shade form of this grass is known to systematists under the 
name D. glomerata var. lobata Drej. It occurs in the beech woods 
of southernmost Sweden, as well as in Denmark, and differs from the 
