253 
The Anatomy of the Mummy Pea. 
large measure independently of the rest of the plant: any inter¬ 
change of water and food-stuffs between the outer and the inner 
systems must take place through parenchymatous and not 
specifically conducting cells. In any case the internal system of 
tissues can have little importance in furthering the development of 
leaves, flowers and fruit: and it is probable that its existence is the 
expression of some morphological determination rather than of the 
need of subserving a physiological function in relation to the whole 
plant. 
As already mentioned, the structure here described belongs to 
the class of abnormalities known as ring-fasciations. In the ordinary 
linear fasciations such as are so frequently seen in Asparagus 
officinale , Crepis biennis , etc., the terminal meristem of the axis is 
broadened in one plane, remaining narrow in others: the resulting 
axis becomes ribbon-shaped in consequence. The peculiar radiate 
fasciation 1 is a simple variant of the linear, in which the lateral 
extension of the meristem takes place in more than one plane, so 
that the axis is strongly winged. In the ring-fasciation, however, 
the meristem is annular. At its inception it may be considered to 
arise by the sterilisation of the apical spot of the normal paraboloid 
meristematic region, leaving the peripheral cells still active. 
Further growth tends to widen the diameter of this ring of 
meristem and at the same time to increase the cavity within : the 
funnel-shaped axis is the result. 2 
Linear fasciation has often been pictured (as indeed the word 
fasciation implies) as the concrescence in a linear series of a 
number of individual branches which in the normal state would be 
free from one another. While there is no foundation in ontogeny 
for such a view, it is useful for the moment to regard ring-fasciation 
from a similar standpoint, for the sake of elucidating the vascular 
anatomy. 
In the adjoining diagram (Fig. 4) six circles (drawn in thin 
continuous lines), are arranged to represent individual stems in 
contact with one another in a ring. In each stem is figured a 
number of normally oriented vascular bundles (xylem black, phloem 
left clear). If we now imagine all these contiguous stems fused 
together into a solid ring of tissue (heavily outlined in the diagram) 
1 H. de Vries. “The Mutation Theory” (Engl. Transl.) II., 
p. 497, 1911. 
2 L. Lutz explains in a similar way what appears to be an analogous 
case in the Phacophyceae—the production of an infundibuliform 
branch in Ascophyllum nodosum. Bull. Soc. Bot. France LVI., 
p. 606, 1910, 
