ST. JOHN: SABLE ISLAND. 71 



P. LAPATHIFOLIUM L. In a potato field, East End Post, J. Macoun 

 (C. no. 22,590). 



FL, Fr. July. 



P. LAPATHIFOLIUM L., var. PROSTRATUM Wimmer. Brackish 

 beach of Wallace Lake near the Main Life Saving Station. H. St. 

 John, no. 1,361 (H). Material of this number was distributed 

 under an unpublished manuscript name. 



FL, .Fr. September. 



P. SCABRUM Moench (P. TOMENTOSUM Schrank). A weed at the 

 Main Life Saving Station. H. St. John, no. 1,213 (H). 



FL, Fr. August. 



P. HYDROPIPER L. Introduced around buildings, Main Life Sav- 

 ing Station, J. Macoun (C. no. 22,582). 

 FL, Fr. August. 



P. PERSICARIA L. A weed at the Main Life Saving Station. H. 

 St. John, no. 1,214 (H). 

 FL, Fr. August. 



P. hydropiperoides Michx., var. psilostachyum, n. var., 

 P. hydropiperoidem simulans sed differt ocreolis glabris eciliolatis, 

 marginibus pellucidis; foliis glabris vel glabratis brevioribus, 4-8 

 cm. longis, 0.8-2.4 cm. latis. 



Differing from P. hydropiperoides, which has leaves pubescent at 

 least on the midrib and near the margins and often throughout, in 

 having glabrous eciliolate ocreolae which have scarious transparent 

 margins, and in the glabrous or glabrate comparatively short leaves, 

 4-8 cm. long, 0.8-2.4 cm. wide. 



NOVA SCOTIA : in muddy ponds and by their borders, Sable Is- 

 land, Aug. 3, 1899, J. Macoun (C. no. 22,583); Sable Island, Sept., 

 1911, H. T. Gussow (E); shallow fresh-water pond, Sable Island, 

 Aug. 16, 1913, H. St. John, no. 1,215 (H); swampy edge of fresh- 

 water pond, Sable Island, Aug. 23, 1913, H. St. John, no. 1,216 

 (TYPE in Gray Herb.). WASHINGTON: White Salmon, Oct., 1880, 

 W. N. Suksdorf, no. 483 (H); Columbia River Bottom, Klickitat 

 Co., Oct. 12, 1881, W. N. Suksdorf, no. 56 (H & P). 



To the last-cited specimen there is a reference in a letter from W. 

 N. Suksdorf to Dr. Sereno Watson, dated Oct. 20, 1881. "It is an 

 indigenous plant no doubt, very frequent on low bottom lands near 

 the Columbia River; perennial, the prostrate stems rooting at the 

 joints, the flowering portion mostly ascending." On the list is a 

 note in Dr. Watson's handwriting, "but bracts not ciliate." So it 



