POTAMOGETON Sp. 2. 

 PI. II, fig. 2. 



Nut obovate truncate at base, flat with large shallow curved central depression, 

 ventral margin convex, dorsal margin semicircular, attachment prominent basal; style 

 sub*lateral directed forward short with parallel sides; keel sharp but not crested, without 

 spines, reaching as far as the style; surface of endocarp not very hard, sculpture irregular 

 cells elongate circumferentially. 



Length (with style) 2 mm., breadth 1.5 mm. Brunssum. 



This species also seems to be confined to Brunssum; its prominent truncate 

 attachment is its most conspicuous character. 



POTAMOGETON Sp. 3. 

 PL II, fig. 3. 



Nut irregularly obovate, flat with small shallow curved central depression, 

 ventral margin angled with broad blunt spur below middle, dorsal margin convex, 

 attachment sub4ateral ; style apical short conical; margins of nut on either side of keel 

 with revolute wings ending in short tubercles below; keel not crested, reaching to the 

 style; endocarp moderately hard, sculptured with coarse irregular pits. 



Length 1.75 mm., breadth (including spur) 1.5 mm. Brunssum. 



We have only seen one nut of this species; but the lateral wings make it quite 

 unlike any of the other forms. 



POTAMOGETON Sp. 4. 

 PL II, fig. 4. 



Nut irregularly obovate, showing very clearly the curve of the seed, compressed, 

 with shallow curved central depression, ventral margin convex above concave below 

 sometimes with a thin wingslike process near the base, dorsal margin convex, attachment 

 basMateral ; style apical at ventral angle, directed inward; keel more or less crested (one 

 specimen shows the crest expanded into a flat wing above) reaching to the style; 

 sculpture of endocarp large cells elongate circumferentially. 



Length 1.75 mm., breadth 1.4 mm. Brunssum, Reuver. 



A common species at Brunssum, and found at Reuver, but very variable. Its 

 most marked character is the conspicuous outline of the seed impressed on the endocarp, 

 in this it resembles P. densus. 



POTAMOGETON Sp. 5. 

 PL II, fig. 5. 



Nut oblong*oval much inflated, with small but deep central depression, ventral 

 margin convex above slightly incurved below, dorsal margin convex, attachment basal ; 



59 



