LARKSPUR POISONIXG OF LIVE STOCK. 19 
cross sections of the main stem of the plant were made without refer- 
ence to any particular point in the stem. In the case of Delphinium 
harheyi and D. menziesii and Aconitum, hakeri, sections were made 
from the subterranean portion of the stem, the petiole, and the 
peduncle. A photomicrograph was made of a portion of a section of 
a stem of each species, all the photographs being magnified 65 
diameters. 
The sections of course showed certain characteristics typical of the 
Ranunculaceae, the most noticeable being the form and disposition of 
the fibrovascular bundles. The bundles are of the closed collateral 
type and are isolated, being separated by wide medullary rays. The 
xjdem mass has in cross section a somewhat V-shaped appearance, the 
arms of the V partially inclosing the cambium and phloem. There 
is no interfascicular cambium. This type of bundle is common to 
the Ranunculacese, but is found almost nowhere else among the dicot- 
yledons (Solereder, 1908, p. 18, and Jeliffe, 1899, p. 339). Another 
feature of the bundle peculiar to the Ranunculacese among dicotyle- 
dons is that the phloem consists only of sieve tubes and companion 
cells, with no phloem parenchyma (Strasburger, 1908, p. 113). 
These facts in regard to the fibrovascular bundles serve to differen- 
tiate the Ranunculacese from other dicotyledons, but are also points 
of resemblance to some of the monocotyledons. Therefore in identi- 
fying larkspurs in the stomach contents of poisoned cattle it was 
necessary to differentiate carefully from some of the grasses when 
only fragments of the stem could be obtained. 
The genus Delphinium has a characteristic stem structure, as shown 
by cross sections. Yesque, 1881, page 28, says that it is impossible to 
distinguish anatomically the genera of the Ranunculacese, but that 
certain groups of genera can be recognized, and he places Aconitum 
and Delphinium in one group. Myer, 1885, page 16, in his key, gives 
means of distinguishing both Delphinium and Aconitum, the latter 
being differentiated from Delphinium by the presence of a complete 
ring of sclerenchyma outside the fibrovascular bundles. 
In cross section the external circumference of a Delphinium stem 
is either approximately circular or approaching an octagonal shape, 
and the stem is hollow. It is covered externally by a layer of epi- 
dermal cells whose outside walls form a thickened cuticle. The epi- 
dermis usually bears unicellular hairs of varying shape, size, and 
number, and is pierced by simple stomata. Beneath the epidermis 
there is a layer of hypodermal cells similar to those of the epidermis 
but without thickened walls. Inside the hypodermis there are two 
to five rows of cortical parenchyma cells, bearing chlorophyll, ancl 
arranged loosely with intercellular spaces. In one species it was 
possible to distinguish an endodermis, but as a rule the endodermis 
can not be distinguished from the other cells of the pericycle. The 
