358 ROYAL SOCIETY OF CANADA 
The passage from Russow (15) which has been noted above is now 
introduced, and Potonié’s (13, 25) observations follow. 
“The lacunar parenchyma (Liickenparenchym) of Russow, in 
front of the protohydron, in the inbending angles of crooked plates 
(Hydroiden-Platten) in the stipe of many ferns, forms a peculiar struc- 
ture, the significance of which is very obscure.” 
“The cells of this tissue possess a wider lumen than the other 
vascular parenchyma, and their walls are bent in and out in such a 
manner as to cause large intercellular spaces. It is found, e.g. in the 
stipe of Dicksonia antarctica, Blechnum spicant, Asplenium angusti- 
folium, ete.” 
Potonié does not attempt to interpret the structure at all, and 
merely notices that its significance is obscure. 
Terletzki proceeds with his own observations, which deal with the 
contents of the cells under discussion. 
“The Stumpfzellstringe observed by me in the rhizome of Stru- 
thiopteris germanica, outside of some remains of protoplasm, contained 
only starch, and so I cannot agree with Dippel’s statement that this 
tissue is set aside for the reception of secretions, and must be placed side 
by side with the resin, mucilage, and lactiferous passages of the phane- 
rogams. J am more of the opinion that these are essentially of the same 
functional value as the conducting cells, for they differ from these only 
in form and size, but agree with them in the structure of the wall and 
in contents.” He then goes on to show that Russow’s interpretation of 
these cells as phloem elements is erroneous, and states that they must be 
regarded as parts of the xylem parenchyma (18, 465). However, al- 
though he criticises both Dippel and Russow correctly, he himself failed 
to give a correct interpretation of the structure. 
The statements made by-Russow as to the irregularity of the spiral 
tracheids adjacent to the “ Zellstränge,” and as regards the brownish 
discoloration of the cell walls in mature bundles, were confirmed by 
Terletzki’s observations on Struthiopteris germanica. 
In the description of the sterile stipe of Struthiopteris germanica 
(18,479), Terletzki mentions the same structures in the vascular bundle. 
The “ Zellstränge ” invariably accompany the protoxylem groups, being 
adjacent to them, and running parallel with them. Since there are four 
or five patches of protoxylem in the bundles of this form, the same num- 
ber of “ Zellstränge ” is encountered. As in the rhizome, the cells com- 
posing these strands are thin-walled and contain small quantities of 
starch. 
Terletzki evidently perceived some relation between the “ paren- 
RS Ee 
