OF NAIAS GRAMINEA, VAR. DELILEI. 69 



largely used in Bolton, the mill-ponds and canals of that 

 neighbourhood may be expected to contain Naias graminea 

 and other Egyptian aquatic plants, as Naias muricata, Del., 

 Char a Braunii, Gmel., &c. 



The Egyptian origin of the plant is to some extent 

 confirmed by the form of Chara Braunii which grows at 

 Reddish being very near the form of that species which 

 occurs in Northern Africa. Whether there is anything 

 showing an affinity to the Egyptian plant in the peculiar 

 form of ZannicheUia which grows in the same canal, I 

 have not the means of determining ; but both it and the 

 Chara Braunii are so often associated together as to give 

 a strong colour to the surmise of their common origin. 

 There is nothing in the recorded distribution of Chara 

 Braunii, however, to forbid its being ultimately shown to 

 be aboriginal ; but until it is recorded from other British 

 stations, with fewer doubtful surroundings than it has in 

 the Manchester station, it can only be looked upon as a 

 colonist. 



XIX. A Histological Peculiarity. 



A strong proof of its Egyptian extraction is furnished 

 from the histological side. This part of the case has been 

 dealt with by Dr. Magnus, in a paper read to the G-erman 

 Botanical Association at Berlin, December nth, 1883, and 

 I make no apology for reproducing here the substance of 

 this interesting communication. In describing the struc- 

 ture of the leaves of Naias graminea on page 46, I 

 mentioned that there were two forms of the plant — one 

 possessing peculiar libriform cells near the margin of the 

 leaf; the other destitute of these bast-cells. This latter 

 form Dr. Magnus names the var. Delilei, and he states 

 that the English specimens belong to this variety, and 

 indubitably prove their Egyptian source. The following 



