Standley — A New Species of Iresine from the United States. 173 



alluvial soil on the south side of Plummers Island, in the Potomac River, 

 JNIontgomery County, Maryland, October 4, 1915, by Paul C. Standley 

 (No. 12,500). 



Additional specimens examined: Maryland: Plummers Island, 1896, 

 Topping ; in 1903, Kearney 173; Oct. 18, 1896, Pollard, Topping & Olds 

 (no other locality is given than the heading of the label, which is 

 " District of Columbia," but the specimens probably came from 

 Plummers Island). Tennessee: Knoxville, 1898, Euth 182. Nashville, 

 1877, Ward; in 1883, Gattinger. Alabama: In 1878, Mohr. Missouri: 

 Eagle Rock, 1890, Bush 445. Lakeside, 1908, Bush 5160. Kansas: 

 Arkansas City, 1891, Car/c^on 486. Oklahoma: Palmer 281. Cimarron 

 River, 1895, /. U. Kimmons. Near Jennings, 1896, Ward 36. Sapulpa, 

 1894, Bush 482. Texas: Lindheimer 1111. Columbia, 1899, Bush 336. 

 Near Houston, 1898, Thurow ; in 1912, G. L. Fisher 176. 



The writer has also seen other specimens of this species in the her- 

 barium of the New York Botanical Garden and in the Gray Herbarium, 

 but unfortunately no record of them has been kept. 



The occurrence of the plant upon Plummers Island is of great interest, 

 for the station is the northernmost locality now known for the species 

 and for the genus. It seems probable that seeds have been brought down 

 by the Potomac from some locality in the mountains, although the genus 

 is not known upon the east slope of the AUeghanies ; or perhaps the plants 

 are the last survivors of ancestors which had a wider range in Maryland 

 and Virginia. There are several colonies of the plant upon Plummers 

 Island consisting of numerous individuals, but in 1915 only two or three 

 plants flowered. 



