88 Macfarlane—Observations on Some Hybrids 
Detailed comparison of the leaves, flower stalks, inflores- 
cence, flowers and period of blooming, still further confirmed 
the suspicion entertained on findingthem. Histological inves- 
tigation of the three, as well as of D. rotundifolia, which was 
only sparingly present in the marsh, shows that the last- 
named species does not contribute to the formation of the 
plants in question. It equally demonstrates a minute blend- 
ing, in all parts of the hybrids, of the histological peculiarities 
of D. filiformis and D. intermedia. 
When the eleven specimens were collected, care was taken 
to remove sods of both parent species, and all three were 
grown in neighboring flats in the greenhouse. The parent 
species matured an abundance of what seemed to be good 
seeds. The contents of the hybrid pods were apparently 
useless. A detailed description of the macro- and micro-mor- 
phology of each will now be given under the following heads: 
(2) leaves, (4) axis of inflorescence, (c) inflorescence, (d@) period 
of blooming, (¢) size and color of the blooms, (/) floral struc- 
ture. 
(2) Leaves.—The leaves of D. filiformis (Plate XII, Fig. 1) 
are on the average 8 inches long and ;, inch wide. The 
statements made in current botanical manuals that there is 
“no distinction between blade and stalk,” * also that they are 
“ slandular-pubescent throughout,” + are equally incorrect. A 
non-glandular portion 3% to 54 of an inch long is the petiole, 
and in the winter bud-leaves is the only part developed for 
protective purposes. The base of this non-glandular part isa 
flattened quadrangular area % inch by ¥f inch. It is densely 
tomentose-pubescent along its lateral and upper margin, as 
well as externally. The individual hairs vary greatly in size, 
in the number of cells composing each, and in the amount of 
their branching. While some consist of a few cells joined 
lengthwise into a long thread which may give off one or two 
* Gray’s Manual of Botany, 6th edit., 1889. 
} Britton and Brown’s Illustrated Flora, Vol. II, p. 162. 
