O H .A. E. A. C E! -^: . 



Plants growing under water in ponds and slow streams, resembling 

 AlgsB, with which they are classed by some authors. Some of 

 the species have the very disagreeable odor of sulphuretted hy- 

 drogen. The classification is taken from a recent paper upon 

 the subject by Byron D. Halsted, D. S. (Proc. Bost. Nat. Hist., 

 Vol. XX, p. 169; March 5, 1879). The specimens have all been 

 identified by Prof. Parlow and Dr. Halsted, to whom the writer 

 would here acknowledge his indebtedness. 



NITELLE.E. 



Nitella opaea, Ag. 



Specimens of a Nitella collected at Swampscott in a spring hole. 

 May 11, 1879, are referred to this species by Dr. Parlow, who says : 

 — "The specimens are all male, and the plant seems to be dioe- 

 cious. If I am correct in supposing it to be dioecious, the species 

 belongs to the group of N. capitata, to which N. syncarpa, N. cap- 

 itata, and N. opaca belong. The color is lighter than most forms 

 of N. opaca, but I am disposed to refer it to that species which it 

 resembles in habit" (Letter, Nov. 16, 1879). This determination 

 has since been confirmed by Nordstedt (note. Dr. Farlow, Jan. 8, 

 1880). 



Nitella flexilis, Ag. 

 Common in ponds and streams. Chebacco pond ; Merrimac river, 

 above the dam at Lawrence ; in a somewhat brackish stream near 

 Burley Farm, Danvers; Wenham pond. Dr. Halsted refers to 

 certain Essex county specimens as approaching the 



Var. nidlflca. (Chara glomerulifolia, A. Br.), and (N. flexilis, var. 

 subcapitata, A. Br.). 



He also speaks of specimens of this species as having been col- 

 lected in the " Merrimac (Green)," probably B. D. Greene. 



Nitella gracilis (Sw.), Ag. 

 Chebacco pond, near Whipple's boat-landing. The specimens are 

 all of the delicate form. 

 (146) 



