4io West, — A Contribution to the Study of the Marattiaceae. 
it is impossible to demonstrate any satisfactory evidence of phyletic 
relationship. 
The geographical distribution of the living genera of Marattiaceae 
suggests that these plants represent the remnants of a much larger group, 
which, according to the available evidence derived from what is pro- 
visionally believed to be their palaeontological record, dates back to the 
lower coal measures. 
A considerable number of fern-like fructifications, e. g. Ptychocarpus 
(Renault, 50), Cyathotrachus (Watson, 67), Scolecopteris (Strasburger, 63), 
Danaeites , &c., bearing a striking superficial resemblance to the sporangia 
or synangia of the modern genera of Marattiaceae, have been described 
from palaeozoic strata. Among these fossil fructifications are found types 
which closely resemble the spore-producing members of each of the 
surviving genera ; this fact in itself would indicate that the modern genera 
of Marattiaceae are of equal antiquity, and suggests their possible multiple 
derivation from some primitive stock or plexus. As Bower ( 8 , p. 73 ) 
pertinently remarks, perhaps no feature in the Marattiaceae is more 
remarkable than the persistence of type from the remote past to the 
present day. 
Unfortunately, however, we cannot at present fix upon any links from 
strata of more recent geological eras, and, moreover, it is quite possible that 
all, or most, of these fern-like fossil fructifications which have been referred 
to the Marattiaceae are in reality the male fructifications of Pteridosperms ; 
this evidence should therefore be accepted with reservation. 
The doubts cast upon the hitherto generally accepted view of the 
Marattiacean affinities of the fossil genus Psaronius by Farmer and Hill 
(39, pp. 382 - 3 ) have been materially strengthened by the recent observations 
of Solms-Laubach (60) on the anatomy of this genus. 
Summary. 
1 . A comparative account of the structure and development of the 
stelar system in the Marattiaceae, with special reference to the adult 
sporophyte of Danaea , is given, and the question of the symmetry of the 
sporophyte in this group of Ferns is discussed. A primitive radially 
symmetrical type of shoot is distinctly suggested. 
2 . The single apical cell found in the apex of the. stem of the young 
sporeling is later replaced by a group of equivalent . initial cells or by 
a meristematic region. 
3 . A single large apical cell occurs at the apex of the primary and 
earliest adventitious roots. At the apex of the later adventitious roots 
of moderate size a group of about four equivalent initial cells is found, 
while the more robust roots generally possess a definite meristem consisting 
of a number of independent initial cells. In brief, the number of initial 
