OF NAIAS GEAMINEA, VAR. DELILEI. 



41 



and the form of the auricle when present^ furnishing useful 

 marks of discrimination. The types given by Braun in 

 the ''Journal of Botany/ vol. ii. p. 274^ are redrawn on 

 Plate VI. figs. io-i4j but, as will be seen from what 

 follows, the E-eddish plant differs considerably from Braun^s 

 figure of N. graminea, unless he meant it to serve as a 

 general figure of the type of sheath in his super-species 

 N. tenuifolia. 



In the English Naias graminea the base of the lamina 

 of the outermost pair of leaves suddenly dilates into a pair 

 of upright auricles or ears, which are continued below so 

 as to form a more or less ample sheath (see fig. 52) ; the 

 size of the sheath presents considerable variations, accord- 

 ing to the age and the position of the leaf to which it 

 belongs (see figs. 52-55). I see no trace of any intra- 

 vaginal scales (squarnulse) at the base of the leaf-sheath, 

 such as are found in Naias major and in the allied genus 



I'ig- S3- 



