216 BOTANICAL GAZETTE [SEPTEMBER 
Brachyphyllum, and THomAs (28) on Taxites. In addition to these, 
there are many scattered references to the distribution of stomata 
in the description of coniferous leaves, as by JEFFREY (14), BERRY 
(3), SropEs (26), and Stopes and KersHaw (27), but too often there 
has been no attempt at correlation with living forms. 
In the structure of the epidermis there are certain features which 
are constant, and certain others which seem to vary, not only 
within the genus or species, but even in different individuals. 
For example, in the case of flattened dorsiventral leaves of 
the Taxites type, the stomata are always abundant on the 
lower surface, but may or may not be present on the upper as 
well. Thus Matuert (16) states that in Sequoia sempervirens, 
Abies, and Pseudotsuga they are present on both surfaces, but I 
have found many instances where they were completely lacking 
above. As regards numbers, such a character must obviously 
vary, and even a hasty examination shows flaws in the elaborate 
keys of BERTRAND (6), where Arducaria excelsa is described as 
having 3 nerves, and 4 groups of stomata -of 5 rows each; A. 
Balansae, with 5 nerves, and 4 groups of stomata of 8 rows each, 
etc. This is commented on by Sewarp and Forp (25): “The 
veins vary in number in the leaves of a species according to the 
part of the lamina examined and the age of the leaf. The rows of 
stomata exhibit similar varieties; for example, Araucaria imbricata, 
said by BERTRAND to have 70 rows, may have any number from 
60 to 80.” 
As regards arrangement of the stomata with reference to each 
other, there seems to be remarkable constancy. Thus in practi- 
cally all leaves of the Taxites type, they are in regular rows on each 
side of the midrib, with the long axis of the stoma parallel with the 
edge of the leaf. This seems to hold irrespective of the family 
to which the specimens belong: Pseudotsuga, Tsuga, Abies, and 
Keteleeria in the Abietineae; Widdringtonia in the Cupressineae; 
Cunninghamia and Sequoia sempervirens in the Taxodineae; Taxus, 
Cephalotaxus, and Torreya in the Taxineae; and Prumnopitys and 
Saxegothea in the Podocarpineae. 
The character of the epidermal cells has not been fully described 
by most investigators, but there is every reason to regard it as 
