ON NAIAS GBAMINEA DEL., VAB. DELILEI MAGNUS. 



11 



with them so regularly oval nor so acute as they are represented in 

 Braun's figure (fig. 14, Plate 251) ; on the contrary, I never find them 

 acute, and, though somewhat parallel-sided, they gradually taper 

 from their base to their elongate truncate apex (see figs. 52 and 54). 

 More often than not the auricle is larger on one side than the other, as 

 in figs. 54 and 55. The auricles are confined principally to the first 



Fia. 54. 



Fia. 55. 



pair of leaves of each fascicle, and the sheaths of the pair embrace the 

 leaf; most often these are the only leaves in the fascicle which 

 possess auricles (see Delile's figure on Plate 250, fig. 4). The next 

 pair of leaves has auricles which, when present, form a more acute 

 sinus with the lamina (fig. 55) ; but as we approach the centre of 



each fascicle the leaves are 

 destitute of auricles, and 

 pass into short lanceolate 

 bracts, in the midst of 

 which we find the flowers. 

 In Scotch specimens 

 of Naias flexilis the leaf- 

 sheath is of another type ; 

 the base of the limb widens 

 out into a sheath more than 

 twice the breadth of the 

 limb, and at an angle of 

 about 45° ; but there is no 

 approach to an auricle on 

 either side. The shoulders 

 of the sheath are crowded 

 with teeth, but they are 

 infrequent on the sides. 

 Fio. 56. Fig. 57. See figs. 56 and 57, and 



