86 
Pirola uniflora L. 
(Fig. 4.) 
The specimens are from Finmark: Alten (July 6, 1885, 
Warming). The Danish specimens are from Tidsvilde Hegn and 
from Hornbek Plantage. 
This species differs from the three described above in 
regard to the leaf, the inner structure of the latter being much 
Fig. 4. Pirola uniflora. 
1, Leaf in transverse section; below the epidermis 
of tbe upper surface (es) a palisade-like layer of 
cells is seen. Cf. note p.81. 7, 2 and 3, X about 
120; 4 X about 250. (Finmark: Alten) (H. E. P.) 
more dorsiventral, and 
arranged on the whole 
in a typical manner. 
The epidermis of the 
upper and lower surface 
have only slightly thick- 
ened outer walls and 
much undulating lateral 
walls. Stomata occur 
only on the lower surface 
and are slightly projecting. 
Hairs are absent. Chloro- 
phyll grains occur in both 
the upper and lower 
epidermis. 
The upper layer of 
the mesophyll is of pali- 
sade-form, and the cells 
are short and broad; the 
rest of the mesophyll is 
loosely arranged with 
large intercellular spaces, and consists as usual of irregu- 
larly rounded thin-walled cells which branch but slightly and 
are colourless in the spirit-material. 
In Danish specimens 
the palisade-cells were somewhat longer and more slender than 
in the specimens from Alten, otherwise there was no especial 
difference between them. 
