I20 NEW YORK STATE MUSEUM 



POLYGONUM 



Leaves ovate 1 



Leaves oblong or lanceolate 2 



1 Stem ciliate at the nodes, flo-q^ers in racemes cilinode 



1 Stem not ciliate at the nodes, flowers not racemed Convolvulus 



2 Stem armed with recurved prickles sagittatum 



2 Stem unarmed 3 



3 Flowers inconspicuous, in the axils of the leaves aviculare 



3 Flowers in slender drooping racemes Hydropiper 



3 Flowers in erect spike-like racemes 4 



4 Peduncles glandular Pennsylvanicum 



4 Peduncles glabrous Persicaria 



Polygonum cilinode Mx. 



Fringe joint polygonum 

 Rocky places and along fences. Common. July and August. 



P. cilinode brevis «. var. 

 Stems about a foot long, erect, flowers terminal or nearly so. Top of 

 Cobble hill. August and September. This variety seems to be pecuHar 

 to the Adirondack region. It was found several years ago on the sum- 

 mit of Bald mountain on the west shore of Third lake. 



Polygonum Convolvulus L. 



Black bindweed 



Cultivated ground. Raybrook. August. Introduced and a trouble- 

 some weed in gardens. 



Polygonum sagittatum L. 



Arrowhead. Tearthumb 

 Wet ground, swales and ditches. Common. August. 



Polygonum aviculare L. 



Knotgrass. Doorweed 



Hard compact soil. About dwellings, by roadsides and pathways. 

 Common. The erect knotweed, P. erectiini L., is often associated with 

 this species but no representatives of it were seen in North Elba. 



Polygonum Hydropiper L, 



Smartweed. Water pepper 

 Ditches and wet places. Common. August. 



