3* 26. Potamogit. 6. FLUVIAT. Pl.end.ph. 



S. Potamogiion fluitans. Floating riverweed. 



Upper leaves floating, lanceolate oval, narrower at both 

 ends; peduncles long; lower leaves under water, linear, 

 lanceolate acute. 



Pot. natans (?, Poiret Enc. Meth. 5, 579. 

 Pot, fluitans. Roth Fl. Ger. J, 72. 



Ponds and rivers; perennial; August and September. 



Root creeping; stem flat, very long; branches, leafy; 

 leaves reddish green, finely veined, alternate ; sheath wide, 

 spearshape ; spike dense, reddish. 



b. Leaves all of one sort. 



4. Potamogiton lucem. Shining riveriveed. 



Leaves ovate, lanceolate, flat, ending in a short petiole, 

 shining, veined; stipulce the length of the joints; spikes 

 many flowered, crowded. 



p. aquis immersum, folio pellucido lato oblongo aciito, RaiiStfn. 148,2. 

 P. longis acutis foliis, Ger. em. 822, 

 P.lucens, Lin. S. P. 183. 



Running and stagnant waters ; perennial ; June, July. 



Plant keeps under water, with only the spike above the 

 surface ; flowers reddish ; stipulce embracing the stemg 

 leaflike. 



jS. angustifolium. Leaves narrow ; plant smaller. 



p. folio angusto, pellucido, fere gramineo, Raii Syn, 148, 3. 



y. nudum. Leaves ovate, lanceolate ; petioles scarcely 

 margined. 



5. Potamogiton crispum. Crisp riverweed. 

 Leaves lanceolate, alternate, sessile, waved, serrate; 



stipulce with the tip toi'n and ciliate; stem slightly com- 

 pressed. 



Pot. seu Fontinalis crispa J. Bauhini, Raii Syn. 149, 7. 



Tribulus aquaticus minor, quercus floribus, Ger. em. 824, 



Pot. crispum, Lin. S. P, 183. 



Greater Koter caltrops. 



Ponds and slow running waters ; perennial ; June, July. 

 Leaves sunk, obtuse ; peduncles sunk; spike fewflowered ; 

 flowers reddish, remote. 



^. serratum. Leaves serrated ; upper leaves opposite. 



6. Potamogiion lanceolatum. Spearshape riverweed^ 

 Leaves linear, lanceolate, flat, not nicked, verrucose, 



broader than the stipulae, narrow at the base; peduncle 

 thickened, shorter than the leaves; spike ovate, dense, 

 fewflowered. 



