374 West . — A Contribution to the Study of the Marattiaceae. 
an intermediate condition where the strand forks near its base, and ending 
with two independent strands which originate, not from the base, but from 
the lateral margins of their respective gaps (Text-fig. 4, A and B). 
The root-traces are inserted directly upon the outer surface of the 
internal vascular cylinder of the stem (Text-fig. 4, B). 
Eventually a commissural strand (Text-fig. 4, B, c.s.") is differentiated 
from the inner surface of the internal stelar system, to which it bears 
exactly the same relation as the original commissural strand (Text-fig. 4, A, 
c.s.) does to the external stelar system. 
In the specimen of Danaea alata under discussion, the commissural 
strand of the internal stelar system leaves the inner surface of the cylinder 
near the insertion of a root-trace (Text-fig. 4, B, r.t. 4), and above the gap 
formed by the exit of a compensating strand (Text-fig. 4, B, comp.s. 2) 
B 
A 
Text-fig. 8. a and b. Danaea nodosa , Sm. Transverse sections ot the stem of a large plant, 
showing three concentric zones of bundles and a central strand. adv.b., adventitious bud ; c.s., com- 
missural strand; comp.s., compensating strand; l.t ., leaf-trace; r root. 
passes slowly across the central ground-tissue to the point of insertion 
of the next root-trace (Text-fig. 4, B, r.t. 5) above the gap of the next 
compensating strand (Text-fig. 4, B, comp.s. 3), and thus forms an accessory 
conducting system, which serves to connect up the points of insertion of 
the root-traces. Further complications arise later by the branching and 
anastomosing of the original commissural strand of the internal stelar 
system and by the appearance of a second strand, whilst weak com- 
missures are differentiated across the central ground-tissue and serve to 
join up the two main commissural strands. 
Even in the largest specimens of Danaea alata and of Danaea nodosa 
examined by the present writer, no distinct third vascular cylmder was 
present, the innermost stelar system (if we are entitled to designate it as 
such) consisting only of a few weakly developed anastomosing and branching 
commissural strands (Text-fig. 8, A and B). 
