92 Macfarlanc—Observations on Some Hybrids 
The upper laminar epidermis of D. fi/iformis consists of cells 
which are highly variable in size and shape. Stomata are 
abundant, as many as nine being in a circular area 300 2 
across. Each stoma measures 40 X 30 #. Four-celled sessile 
glandular hairs are also disposed over the epidermis. The 
stomata and glandular hairs of the lower epidermis are about 
equally as abundant as those of the upper epidermis. The 
upper epidermis of D. cxtermedia has on the average seven 
stomata over the above-named area, and each measures 
27 X 22 pw. Two-celled glandular hairs take the place of the 
four-celled ones of the other parent. In the hybrid an 
average of eight stomata is observed in the above area, and 
each measures 34 X 25 p. There is a curious admixture of 
the glandular hairs. Some are two-celled only as in the 
latter parent, others are four-celled as in the former, while 
not a few are three-celled owing to a median or somewhat 
oblique wall crossing one of the twin cells. On the lower 
epidermis the same peculiarity occurs, though in leaves exam- 
ined the majority were two-celled as if the glandular tissue 
swayed toward one parent. Suggestive cytological consid- 
erations come up here of which we shall speak later. Chloro- 
plasts occur in all epidermal cells, but these vary considerably 
in different cells and individuals, so that exact comparison 
seems impossible. 
(6) Axis of Inflorescence-—Comparison of a considerable 
number of axes of the parents with the eleven of the hybrid 
indicates that the average height of that in D. filiformis is 934 
inches, in D. zntermedia 5% inches, and in the hybrid 634 
inches. Here it should be noted that the average heights 
given for the parents have been taken from plants growing in 
several localities, and that the hybrids do not seem to have 
attained the age vigor which may yet be expected. This may 
to some extent affect the length of the axis. 
Surface views of the epidermis of the axis show a quite 
glabrous surface in D. jiliformis with stomata in considerable 
