10 



is subsp. leibergii (Morong) Porsild. Range extends from Quebec and 

 northern Maine west to Isle Royale, Michigan, Saskatchewan, 

 Northwest Territories, Alaska, and British Columbia, south to 

 northwestern Montana, northern Idaho, and Washington. 

 Rare and endangered plant lists: Maine, New England; under consid- 

 eration by the U.S. Fish and Wildlife Service, Office of Endangered 

 Species for listing under the Endangered Species Act of 1973. 



alkalinity: mean 24.8 mg/1; range 13.5-40.0 mg/1; (4) 



pH: mean 7.1; range 7.0-7.3; (4) 



Nuphar (Yellow Water-lily, Spatterdock, Cow-lily) 



Perennial, arising from large, cylindrical, creeping rhizomes; 

 leaves submersed when young, becoming floating and/or erect, 

 blades deeply cleft, with long petioles; flowers globose, floating or 

 elevated above surface; sepals 5-6(-9), yellow, sometimes greenish or 

 reddish tinged; petals numerous, yellow, small, strap-like resembling 

 the stamens; stamens numerous, filaments flat; stigmas sessile, 

 radiate on a disc; fruit an ovoid, leathery berry, with numerous non- 

 arillate seeds per locule, maturing above the water surface. 



The treatment of Nuphar by E. O. Beal (1956), not followed here, 

 recognized only one species, N. lutea (L.) Sibth. and Smith, in the 

 world, with nine subspecies. 



Key to Species 



1. Leaf blades of mature plants 3.5-20 cm long, 3.5-14.5 cm wide; fruit 



conspicuously constricted below the stigmatic disc (fig. 7B,D). 



2. Flowers 2 cm or less wide; stigmatic disc with 6-10 deep crena- 



tions (fig. 7B), leaf blades 3.5-10 cm long, 3.5-7.5 cm wide; blade 



notch two-thirds or more the length of the midrib (fig. 5A). 



1 . N. pumila 



2. Flowers 3 cm or more wide; stigmatic disc with 8-15 shallow 

 crenations (fig. 7D); leaf blades 5-20 cm long, 4.5-14.5 cm wide; 

 blade notch one-half the length of the midrib (fig. 5B). 



2. N. Xrubrodisca 



1. Leaf blades of mature plants 7.0-40 cm long, 4.0-25 cm wide; fruit 

 only slightly constricted, or not constricted below the stigmatic 

 disc (fig. 7F,H). 



3. Petiole strongly flattened above and winged (fig. 6B); leaves 

 usually floating (fig. 6A); fruit and inner surface of sepals often 

 maroon or red. 



3. N. uariegata 



