268 BOTANICAL GAZETTE, | November, 
Labiate, Teucrium for instance, it is scarcely perceptible, 
but there are exceptional cases. 
I would like to show that the characteristic element in the 
Cruciferae has an opposite or thirst-exciting effect, and to 
point out the effects of citric, amygdaline, malic, nutty and 
other odors, but enough has been said to illustrate my mean- 
Ing. 
BRIEFER ARTICLES. 
A Study of Silphium perfoliatum and Dipsacus laciniatus in regard 
to inseets.'—The upper surface of the leaf of Silphium perfoliatum near 
the axis is thickly set with small hairs. Their length is on the average 
about .17 mm. They are composed of four cells each having a distinct 
nucleus; the upper one is somewhat enlarged. Some of the hairs are 
colorless, while in some a peculiar brown substance was seen which was 
variously distributed, sometimes in masses at the top of the upper miei 
diffused through the upper cell, and sometimes through the lower ones 
as well. These hairs point toward the tip of the leaf. Similar hairs were 
found all along the mid vein, side veins and veinlets of the upper sur 
face of the leaf, and also on similar portions of the under surface. No 
difference was seen between these hairs and those near the axis, except 
that they were much more thickly set along a surface about an inch 
length at the base of the leaf. The leaf examined was about 20 em. 
lung and was typical. 
The brown material does not seem peculiar to the hairs. Upon the 
upper surface of the leaves were found some more very small pike 
composed of two cells, the upper very pointed, the lower one co 
and containing an onion-shaped mass of brown matter similar in appeat 
ance to that in the hairs. In the epidermal cells of the stalk were found 
‘similar masses, and some cells were completely filled with it. 
The cavities formed by the perfoliate leaves are very small and hold 
but a few cubic centimeters of water. They are full after any rain oF 
heavy dew, but are often dry before noon. If cups are dry at night they 
will be filled in the morning when there is a heavy dew; otherwise they 
will be dry. 
These cups do not appear to serve any purpose as insect on 
No insects were seen in any of the cups. This plant is not native here; 
and perhaps it does not show its full development with us. 
Is Dipsacus laciniatus insectivorous? To answer this question = 
the purpose of the following observations: 
It is well known the connate leaves of this plant form cups = 
leaves of this plant form cupY 
fk Read 
; at meeting of A. A. A. S., New York, August, 1887. 
? Lansing, Michigan, f 
