POLYGON ACE M. 



[POLYGONUM. 



Inflorescence terminal, racemose spicate or 

 capitate : 



Inflorescence in elongate stout or filiform 

 racemes or spikes : 

 Nutlets biconvex : 

 Bracts hairy : 



Bracts coarsely hairy or strigose ; 

 Leaves ovate, petioles 11 in. long . 

 Leaves lanceolate, petioles less than 

 -J in. long .... 



2. P. orientale. 



Bracts densely hite-woolly . .4 

 Bracts glabrous : 



Perianth not glandular, ochreae usu- 



ally eciliate . . . .5, 

 Perianth glandular, ochre se shortly 



ciliate . . . .6, 



.Nutlets triganous : 



Racemes stout and short, with closely 

 imbricate bracts, perianth not glan- 

 dular : 



Bracts more or less hairy . . 



^Bracts glabrous : 



Leaves tapering to the acute base, 

 marginal cilia of ochre se longer 

 than the tube . . . 



Leaves tapering to a rounded or 

 subcordate base, marginal cilia of 

 ochreae not longer than the tube 



/Racemes slender, filiform, bracts more 

 or less distant : 



Perianth glandular ; stems shortly 

 creeping below ; nutlets not 

 polished : 



Ochreae very shortly ciliate or eci- 



liate ; bracts glandular or not . 



Ochreae with cilia at least half as 



long as the tube ; bracts always 



glandular 



P. limbatum. 

 P. lanigerum. 



P. glabrum. 



P. lapathifolium. 



7. P. stagninum. 



8. 



P. barbatum. 

 P. serrulatum. 



10. 



.Perianth not glandular, very small ; 

 stems extensively creeping below ; 

 .nutlets polished . 



11. 



12. 



P. Hydropiper. 

 P. flaccidum. 



P. Posumbu. 



