10 



3. Myriophyllum farwellii Morong Fig. 3, Map 4 



Uncommon in acid ponds and streams of northern New England. 

 Sterile plants of M. farwellii can be easily confused with M. humile 

 and M. alterniflorum. Positive identification requires fruit or presence 

 of turions. The black-spiculate vegetative character used by Fernald 

 (1950) to distinguish M. farwellii is sometimes observed in M. humile. 

 In New England M. farwellii is restricted to northern states, while 

 M. humile is chiefly distributed in southern New England. Range 

 extends from Newfoundland and Nova Scotia west to northern Mich- 

 igan and central Minnesota, south to Maine, New Hampshire, Ver- 

 mont, and central New York; British Columbia. 

 Rare and endangered plant list: New Hampshire 



alkalinity: mean 7.2; range 3.0-9.5 mg/1; (3) 



pH: mean 6.6; range 6.1-7.1; (3) 



4. Myriophyllum alterniflorum DC. Fig. 2, Map 5 



Widely scattered in lakes and rivers of northern New England; 

 uncommon to rare in southern New England. The leaf width varies 

 considerably. Plants with short compact leaves have been separated 

 as M. alterniflorum var. americanum Pugsley, but Aiken (1981) notes 

 that this condition appears to develop in low nutrient environments 

 and nomenclatural recognition is unwarranted. Range extends from 

 Newfoundland to Alaska, south to Nova Scotia, New England, north- 

 ern New York, northern Michigan, and northern Minnesota. 

 Rare and endangered plant lists: New Hampshire, Massachusetts, 

 Connecticut 



alkalinity: mean 21.9 mg/1; range 5.0-78.0 mg/1; (17) 

 pH: mean 7.2; range 6.5-8.0; (17) 



5. Myriophyllum pinnatum (Walt.) BSP. Fig. 4, Map 6 



Rare, on peaty and muddy shores of southeastern Massachusetts 

 and Rhode Island. Last collected in 1951 in Falmouth, Massachusetts. 

 This species is found close to the ocean with the exception of the 

 Worcester County, Massachusetts population. Range extends from 

 southern New England west to West Virginia, Kentucky, Illinois and 

 Iowa, south to Florida, southwestern Oklahoma, and Texas. 

 Rare and endangered plant list: Massachusetts, New England 



6. Myriophyllum uerticillatum L. Fig. 5, Map 7 



Uncommon, in quiet waters of lakes and streams throughout 

 New England. This species was last collected in Connecticut in 1920 

 and in Massachusetts in 1943. It appears that it cannot compete with 

 more vigorous species of Myriophyllum, but may also be sensitive to 

 pollution. The best field characters for identification include bracts 



