Vol. XV, pp. 11-13 February 18, 1902 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



/^: 



THE LARGE YELLOW POND LILIES OF THE 

 NORTHEASTERN UNITED STATES. 



BY GERRIT S. MILLER, Jr. 



Plants of two very distinct types, the general aspect of 

 which is shown in the accompanying illustration (plate ii), 

 occur among the large Yellow Pond Lilies of the North- 

 eaBtern United States commonly known as Nymphma advena. 

 Throughout New England (with the possible exception of parts 

 of Connecticut), New York (except Long Island and the lower 

 Hudson Valley), and the mountainous portions of Pennsylvania, 

 plants with floating leaves are the invariable rule, while from 

 the region of Washington, D. C, north through the lowlands 

 east of the Alleghenies to Long Island and the lower Hudson 

 Valley an erect plant is found to the complete exclusion of the 

 other. The ranges of the two types are thus seen to coincide 

 with the boundaries of the life areas of the region, that of the 

 floating-leaved form embracing the boreal and transition zones, 

 that of the erect plant the upper austral zone. In the New 

 Jersey Pine Barrens the two types are found together; but this 

 is scarcely an exception to the rule, as the biota of the region 

 abounds in such juxtapositions of northern and southern forms. 

 West of the Alleghenies the ranges of the two types are very 

 imperfectly known, though so far as understood they again 

 coincide with the life zones. The erect plant is found in Illi- 



3-BlOl-. SOC. Wa«H. Vot. XV. 1902 (11) 



