312 KINGSLEY: SPLITTING OF RHIZOME OF DELPHINIUM 
necrotic pith. Undulations appear in the outer endodermis, 
one of which develops into a deep cleftlike projection through the 
rays between the bundles and toward the center of the stem, from 
which the inner endodermis extends out to meet it. By the 
union of these the stem is divided on one side. This phemomenon 
may occur simultaneously in more than one radius, thus dividing 
the section into several parts. But in each case this method holds 
good, and in each case either one radial bundle mass is separated 
off into a circular column, or more are cut off into a sickleform 
group. 
In his discussion of splitting in Gentiana cruciata,* Jost describes 
the division as being due to the separation of parts, by a row of 
newly originating cork-covered parenchyma cells, which he calls 
‘‘beriderm.” This he considers to be-a single layer of cells that 
have been separated off and become corky, not in any way to be 
considered phellogenetic in origin. The pith also is cut off by an 
inner periderm originating from a cork cambium, which pushes out 
into the wood parenchyma between the fusion bundles in order 
to meet this ‘cortical periderm.” This ‘“ periderm”’ as described, 
exactly agrees with the ‘‘endodermis’’ found in D. scaposum. 
Following the invasion of the central necrotic region by the 
endodermis, the parenchyma isolated between the two sides of 
the cleft dies and forms a continuous link between the necrotic areas 
from center to periphery. In response to the death of the tissue 
there is the formation of a cork layer similar to wound periderm, 
which protects the living tissues inside from the decaying surround- 
ing tissues. Jost also corroborates this interpretation when he 
says, in speaking of Gentiana cruciata and Corydalis nobilis,t 
that the periderm is the consequence of necrosis of tissues, and the 
necrosis of tissues in both cases must have an inner cause. We 
find cork formation taking place on all sides of the split-off columns. 
This cast-off periderm on the outside easily disappears in the 
earth. But in cases where we find a complete circle of columns 
still seemingly bound in one trunk (FIG. 2), the rotting central 
““‘bark’’ cannot be cast off and necessarily accumulates. This large 
mass of dead material can hardly be all attributed to cork forma- 
*Jost; Loc. cit. p. 43. 
{ Jost: Loc. cit. p. 476. 
