Birbal Sahni. 
270 
been closed long since, till Velenovsky in 1905 1 propounded his view 
that the stolons of Nephrolepis belong to a new morphological 
category which he called “ Achsentrager ” (shoot-hearer). This 
term, as applied to these organs has been severely criticized by 
Sperlich, and Velenovsky has recently attempted to defend his 
position. 2 Nevertheless, there seems little room for a new morpho¬ 
logical category for the reception of a structure whose cauline 
nature is decided beyond question (p. 255, footnote). It will suffice 
here to summarize in the form of a table the several views that 
have been put forward by various authors regarding the nature of 
the stolons. 3 
Root. 
Shoot. 
Combining Root & 
Shoot Characters. 
An Organ 
sui generis. 
Brongniart 1839 
Trecul 1885 
Kunze 1849 
Hofmeister 1857 
Russow 1873 
Lachmann 1885-9 
Goebel 1889 
Poirault 1893 
Sperlich 1906,1908 
Heinricher 1907 
De Bary 1887 
Velenovsky 1905 
We have seen that the outstanding feature of the stem- 
anatomy of the species of Nephrolepis examined is the presence, 
near the apex, of a primitive type of dictyostele (not far removed 
from a solenostele), while in the leaf-trace we pass from the simple 
arc-like condition ( N . raviosa) to the compound (double in N. altes- 
cnndens , triple in N. volubilis). 
So far as anatomical characters can be a guide to phylogenetic 
position, Nephrolepis would seem to occupy a place in that more or 
less coherent but intricate plexus of forms which illustrates, on the 
one hand, the transition from the solenostele to the dictyostele 
(with concomitant elaboration of the leaf-trace), and on the other, 
the “ phyletic shift ” of the sorus from the margin of the frond to 
its under surface. In the latter respect Nephrolepis is evidently 
well advanced towards the superficial type of sorus. For the 
location of the genus within this plexus of forms more data from 
1 Vergleichende Morphologie der Pflanzen, 1905, vol. I, p. 233, Prag. 
a l.c., vol, IV, 1913, p. 32. 
3 The references up to 1888 will be found in Lachmann, Contributions, 
etc., of the later ones the following may be mentioned: Goebel, Pflanzen- 
biologische Schilderungen, vol. 1, 1889, p. 203, footnote; Poirault, Ann. Sci. 
Nat. Bot., 7 8 ser. t. 18, p. 160. 
