CERTAIN DICOTYLEDONOUS AND CONIFEROUS LEAVES. 261 
Cuticular Structure (Pl. 21. fig. 33, Pl. 20. fig. 34). 
Stomatal Apparatus.—The stomata show a banded arrangement, and 
appear to occur on both sides of the tiny leaf. One band appears to consist 
of four or five rows situated in epidermal pits. The poral axes appear as a 
whole to be orientated lengthwise, but their orientation may be oblique or 
transverse. The pores are usually bounded by four epidermal cells, but five 
epidermal cells surrounding the pore are not uncommon, forming a rosette. 
When four cells surround the pit, two are orientated transversely, and two 
parallel to the direction of the poral axis. One of the transverse cells may 
be much drawn out and longer than the others. This is also seen in the 
modern Glyptostrobus cuticle. The elongated cell may join the next poral 
ring obliquely. 
Epidermal Cells elongated parallel to the long axis of the leaf. One end 
of a cell may be much narrower than the other, owing to the obliquity of 
some of the cross walls. The cross wall may be curved instead of plane. 
One, two, or three rows of epidermal cells intervene between the linear 
series of stomata. A few of the longitudinal walls of the epidermal cells 
show slight sinuations. The epidermal cells intervening between two linear 
series of stomata are somewhat narrower than those in the middle of the 
leaf. One epidermal cell only may separate one pore from the next, of the 
same or an adjacent linear stomatal series, since the stomata may occur very 
close together in a band. | 
Average length of an epidermal cell between two linear series, ‘039 mm. 
Average width of an epidermal cell between two linear series, ‘017 mm. 
Discussion as to the Affinities of Taxodium europæum. 
It has been suggested that possibly Taxodium europeum is a polymorphic 
form of Sequoia. The cuticular structure is, however, distinctive, and does 
not bear out this view. In order to compare it with recent forms, prepara- 
tions of Taxodium distichum and of Glyptostrobus heterophyllus have been 
made, and the cuticular structure of these species will now be described. 
Externally, Taxodium europeum exhibits more likeness to Glyptostrobus 
heterophyllus than to Taxodium distichum, but, as we have seen, external 
resemblances may be fallacious, and considered alone are frequently valueless. 
The cuticles of the three leaves will therefore now be compared before any 
deductions are made. Kräusel, 1919, p. 110, describes Tazodium europæum 
as Glyptostrobus europeus, and considers it externally much like Widdring- 
tonia helvetica, but cones were not found. 
TAXODIUM DISTICHUM, Rich. 
External Characters —Leaves deciduous, distichous, acute, green, not scale- 
like, standing out from the stem at an angle of about 45°, 
