6 INDUCTION, DEVELOPMENT, AND HERITABILITY OF FASCIATIONS. 
or maroon color in the secretory cells of the parts exposed to injury. 
Simple fasciations when sectioned show the traditional structure of flat 
stems and do not vary from the normal except in outline. 
Sections of ring-fasciations, as diagrammed in plate rv, series 3, follow 
closely the description of Nestler (8) for Veronica longifolia in having, 
besides the primary bundle-ring, a second bundle-ring bordering the 
cavity of the funnel. This ring originates as a group of meristematic cells 
in the center of the medullary parenchyma. Gradually successive groups 
of meristem appear, arranged in acircle, and these differentiate into typical 
bicollateral bundle-groups. The earliest group consists of several undif- 
ferentiated cells, which show their first tracheze some sections above their 
initial appearance. The latter groups in their earliest stage consist of 2 
cells side by side, a trachea and a nucleated prosenchymatic cell. The 
parenchyma cells in the center of the pith below the first signs of the ring 
are smaller than the peripheral cells and more crowded together. The 
phyllotaxy of the stem is already changed from the normal below this point, 
so that the loss of definite arrangement is seen to precede the formation 
of the meristems. The secondary bundle-groups gradually increase in size 
and merge together into the ring; there appears in the center of the pitha 
lysigenous cavity, which is the beginning of the hollow of the funnel, and 
further differentiation produces an internal epidermis, cortex, and stereome 
ring, in sequence the exact reverse of the primary arrangement in the 
periphery. At the apex the two bundle-rings merge into one. When the 
side of the funnel breaks, the two rings unite at the break and surround 
the elliptical pith of a simple flat fasciation. As there are leaves and flowers 
within as well as without the funnel, there are leaves and flowers on both 
sides of the banded stem. 
The structure of the groove fasciation of the wild O. dennis, shown in 
plate Iv, series 1, presents a case analogous to this. At an early stage of 
development a portion of the cambium is destroyed, the bundle-ring broken 
through, and the space is filled with parenchyma. The expansion and 
increase of the undisturbed cells results in the constriction g, which is 
the external sign of the groove. In the interstice in the ring a meristem 
develops in the parenchyma, succeeded by other meristems lateral to it. 
These differentiate into a line of bundle-groups which merge with each 
other and with the primary ring. During this process the stem flattens, 
although it is circular when the meristem appears. The flattening is a 
slow and at first imperceptible process, and the beginning of the alteration 
must be sought far below the point where it is visible to the naked eye. 
The distance of the open groove from the tip is 17 to 26 cm.; the stems are 
flat and broad 12 to 19 cm. from the tip; the meristem begins from 2 to 
4cm. below the opening of the groove. The early stages of the process may be 
followed by a reference to plate v, figs.1 to3. Theorigin of the meristem 
