80 



head on a peduncle 10 cm, in length, but I have seen no Amer- 

 ican specimen equal to this. European specimens, also, some- 

 times have the lowest peduncle axillary, showing a variation in 

 this respect. Mr. W. H. Beeby, of London, in a letter to the 

 writer, suggests that our plant maybe 5. simplex, v. longissinimn, 

 Fries, which greatly resembles S. affine, Schnizl, and perhaps 

 some of the forms included here may belong to that variety, a 

 form with which I am unacquainted. 



As stated by Engelmann, this plant sometimes occurs in dwarf 

 states, growing nearly out of water, with shorter erect leaves. 



Mountain lakes and slow streams, New York, New England 

 and northward, also CaUfornia and Washington Territory. (Eu.) 

 5. .S". minimum, Bauhin. (C. Bauhin, pin. 16 Raji, Herb. Norm. 



XIL, n. 71. Fries, Summa veg. Skand., p. 68, 1845. Called 



S. nutans by most of the older writers, but not the true 



5. natmis of Linnseus.) 



L 



Stems more slender than any of the preceding, varying m 

 height according to the depth of the water in which it grows, i-io 

 dm.; leaves thin and lax, 1-5 mm. in breadth; inflorescence 15- 

 40 mm. in length; staminate heads i or 2, pistillate 1-3, sessile 

 and axillary, or the lowest on an axillary peduncle 3-20 mm. 

 long; ripe fruiting heads 5-10 mm. in diameter; nutlets top- 

 shaped, (vid. fig. 9) 2^-31^ mm. long, or sometimes elongated 

 to 4 mm.; stipe ^-i mm. long, or now and then apparently 

 none; styles about i mm. in length, of which the oval stigma 

 occupies from ^ to 



The flowers usually rise to the surface in order to effect fer- 

 tilization, but sometimes this appears to be done and the fruit 

 perfected when submerged. Occasionally dwarf plants are found 

 growing erect out of the water. 



Pennsylvania and New England to Canada and northward; 

 also westward to Oregon and Washington Territory. (Eu.) 

 6. S, hyperboreum, L^st. (In Wikst. Arsberatt, 1850.) 



Stem similar to that of S. mininmm, 20-30 cm. high ; leaves 

 usually shorter and narrower, 1-3 mm. broad ; inflorescence only 

 15-25 mm. in length; staminate heads i or mofe, pistillate 1-2, 

 sessile or the lower on a short peduncle which is often supra- 

 axillary; ripe fruiting heads 5-10 mm. in diameter ; nutlets ob- 



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