70 MR. C. BAILEY ON THE STRUCTURE ETC. 



are some extracts from tlie paper of Dr. Magnus^ pnblislied 

 in the 'Berichte der deutsch. botanisclien Gesellschaft/ 

 Jahrg. 1883, Band i. Heft 10 : — 



"I have examined the specimens of Najas graminea 

 collected by Delile in the rice-fields near Rosetta, as also 

 those obtained by Schweinfurth near Benha-el-assl in the 

 Nile Delta, and have found them to be Tvithout bast- 

 nerves. They are also wanting in a specimen collected 

 by Gaillardet, near Saida in Syiia, which has been kindly 

 communicated to me by M. Boissier. I was farther 

 enabled, through the kind communication of Professor 

 Ascherson, to examine specimens of Najas graminea, Del., 

 collected by him during his travels in the Libyan Desert, 

 in the Oasis of Dachl, as also specimens collected by 

 Schweinfurth in the Great Oasis (Chargeh). From this 

 it would appear that the Najas graminea, Del., collected 

 in a brook at xA.in-Scherif near Kasr Dachl, as well as 

 those collected by Ascherson near El Chargeh, likewise 

 have leaves without hbriform cells, like the plants of 

 Lower Egypt. On the other hand, the N. graminea col- 

 lected some weeks later in the same ditches in Ai'n-Scherif 

 bv Ascherson, as well as from a warm spring-hole in Kasr 

 Dachl, as also the specimens collected by Schweinfurth 

 near Chargeh, have all well-developed bast-nerves, similar 

 to the plants of Cordofan, Djur, Algeria, Celebes, &c. . . . 

 " The absence of these bast-nerves in a variety of Najas 

 graminea is the more peculiar, as through the construc- 

 tion of the male flower of iV. tenuifoVia, R. Br. [see fig. 15, 

 Plate YL], from Australia, which difiers so materially, 

 has precisely the same bast-nerves in exactly the same 

 shaped libriform cells on the leaves ; consequently these 

 bast-nerves represent the distinctive character of a group 



of allied species, but still subject to variations 



'' I have mentioned above that the one set of specimens 



