52 LACKAWANNA AND WYOMING FLORA. 



585. R. OBTUSIFOLIUS, L. BlTTER DOCK. 



586. R. ACETOSELLA, L. SHEEP-SORREL. This, and the two pre- 

 ceding, common European weeds. 



POLYGONUM, TOURN. 

 KNOTWEED. 



587. P. aviculare, L. Common in "door yards" and by well trodden 

 paths. 



588. P. erectum, L. (P. aviculare, var. erectum, 5th ed. Man.) 

 Common. 



589. P. tenue, MICHX. Top of Campbell's Ledge, in herb.; Penob- 

 scot Knob. Dudley. 



590. P. lapathifolium, L. Var. incarnatum, WATSON. (P. incar- 

 natum, ELL.) In Mr. Davis' herb., probably from within limits. 



591. P. Pennsylvanicum, L. Near Kingston, etc. 



592. P. amphibium, L. Shores of the Susquehanna S. E. of Moca- 

 naqua. Dudley. 



593. P. Careyi, OLNEY. Pocono Station, D., L. & W. R. R. Prof. 

 Porter. Near the pond in lower Lackawanna Valley, a doubtful 

 specimen. Dudley. 



594. P. ORIENTALS, L. PRINCE'S FEATHER. Pittston, near D., L. 

 W. R. R. Miss Carlson. Occasional in waste ground near Kings- 

 ton. Thurston. 



595. P. PERSICARIA, L. Frequent. 



596. P. hydropiperoides, MICHX. WATER-PEPPER. Shores of Susq. 

 below Mocanaqua, in herb. Dudley. 



597. P. Hydropiper, L. SMARTWEED. Common. 



598. P. acre, HBK. WATER SMARTWEED. Frequent in swamps. 

 Dudley. 



599. P. Virginianum, L. Shaded rich soil near Kingston. Thurston. 

 Opp. Duryea. Dudley. 



600. P. arifolium, L. TEAR-THUMB. Lower Lackawanna Valley; 

 in marsh W. of Tobyhanna; Leggitt's Gap, etc. Dudley. 



601. P. sagittatum, L. Tobyhanna, 1881. Prof. Porter. Moca- 

 naqua; pond opp. Duryea; Leggitt's Gap, etc. Dudley. 



602. P. CONVOLVULUS, L. BLACK BINDWEED. Frequent. 



