22 6 
Barratt>—A Contribution to our Knowledge of the 
neighbouring strands. This is, in fact, what frequently happens at the 
‘ nodes , the anastomosing and forking of the bundles having in many cases 
no relation to the behaviour of the primary strands, although of course forking 
of the primary strands does occur. Such 
lateral connexions were observed by Browne 
(2, p. 258) in the * internodes ’ of the cone of 
E. maximum , and dismissed as not being 
palingenetic, but were regarded as constituting 
a fresh character in the phylogeny of the genus. 
Such a description, which the present writer 
cannot accept, might equally well be applied 
to much of the metaxylem developed at the 
‘nodes’ (Text-fig. 23). In some cones of 
E . arvense the metaxylem may be so ex- 
tensively developed as to form broad bands 
connecting three or four bundles laterally and 
extending from the insertion of one whorl of 
sporangiophores to another (Text-fig. 22 a). 
The parenchymatous tracts which separate 
the bundles have been identified with foliar 
gaps, caused in the first instance by the 
departure of the sporangiophoric trace. The 
gap, however, does not occur immediately 
above the point of departure of the trace ; 
frequently there is no apparent relation be- 
tween them. Much of Browne’s papers are 
devoted to a careful attempt to explain the 
numerous anomalies which occur in the ex- 
amples she describes. This interpretation of 
the vascular structure of the cone is of course 
bound up with the morphological nature of 
the sporangiophore, and the question will be 
further discussed below. 
Although such species as E. arvense and 
E. maximum show a definite network of strands 
with short meshes, in E. palustre , E. limosum , 
E. sylvaticum , the meshes are more irregular — 
frequently . much elongated — stretching through 
two or more ‘ nodes and in E. palustre even 
extending nearly the whole length of the cone. 
Browne ( 1 , p. 699) ascribes these differences 
to a reduction of the xylem which, operating at the nodes, has produced an 
‘ extension of the parenchymatous meshes upwards, downwards, and 
laterally.’ 
E. maximum. 
