2 Birbal Sahni. 
ant} on the Cyatheaceae and Ferns of Cyatheoid affinity besides 
some other forms. 
On taking a bird’s-eye view of the subject it was observed that 
many of the forms fell into a rather striking series illustrating 
progressive stages in the specialization of the branch for the 
purpose of vegetative propagation. This progression appeared to be 
as clear and unmistakeable in respect of the vascular structure, as 
in respect of the external appearance of the branch : the two lines 
in fact ran parallel to each other and rendered more or less mutual 
support. 
But the interpretation of the series in terms of a phylogenetic 
relationship between its different stages seemed to be a difficult 
question, for, as will be seen, the different genera did not necessarily 
stand towards each other in relations corresponding to those 
subsisting between the respective forms of branching exhibited by 
them. 
II. T YPES OF FlLICINEAN BRANCHES AND THEIR VASCULAR 
System. 
It is well-known that in many species of Nephrolepis thin 
cylindrical stolons arise from among the crowded leaf-bases and, 
spreading in all directions from the main stock, grow out to varying 
lengths, and serve as efficient organs of vegetative reproduction by 
bearing so-called lateral plants at intervals. Under suitable 
conditions the growth of the stolons is so rapid that in a single 
season the mother plant may become surrounded by a small colony 
of young plants which eventually become independent, but even 
before doing so may, in turn, produce stolons themselves. Sperlich 1 
sees in the production of these stolons the beginning of an attempt 
towards the attainment of an epiphytic habit; and to what a degree 
this attempt has been successful is well seen in Nephrolepis volubilis. 
Attention was drawn in a previous communication 2 to the extra¬ 
ordinary habit of this interesting Malayan Fern. The mother-plant 
is rooted in the soil, but the stolons are of such a great length that 
they carry the lateral plants borne on them high up among the 
neighbouring trees. It is a case, in short, of a terrestrial plant 
producing an epiphytic progeny. The epiphytic tendency so 
strikingly shown by the genus Nephrolepis may possibly be connected 
with a more effective vegetative propagation which would be ensured 
by the favourable position of the lateral plants. 
1 Sperlich, A., Flora, 1908, p. 357. 
2 Sahni, B., New Phytologist, 1915 , p. 251 . 
