2 3 



striae not very prominent, its surface covered with a close felt "of 

 knotted fibres" (Nordstedf). 



The stem of this species is fine, 300 to 400 in diam. The leaves are 

 longer and the verticils looser than in tenuissima, though in some of its 

 contracted forms it resembles that species. In its diffuse, much branched 

 habit, with open spreading verticils, it resembles N. mttcronata, and 

 differs from N. tenuissima. In the series of connecting forms standing 

 between those species this (gracilis) stands next to mucronata. 



It is not common in America. The specimen from which the draw- 

 ing was made was gathered in Gorham, New Hampshire, by Prof. Far- 

 low; it is reported also from Canada (Engelmann) and Texas (Lind- 

 heimer). 



A form collected many years since in Louisiana by Josiah Hale and 

 found in the herbaria of Engelmann, St. Louis, and Gray, Cambridge, 

 bearing the name " Chara foliosa," must be referred to this species 

 as forma divaricata Migula. It has the following characters: Stem 

 elongated, 415 in diameter, simple, bearing remote verticils. Verticils 

 consist of six leaves, the first segment of which is half the length of the 

 whole leaf (entire leaf about 15 mm. long, to tip of mucro), 150 to 170 

 in diameter. Thejfirsf node bears six divisions, and is usually sterile ; 

 second segments 75 to 85 in diameter. The second node bears 4 or 5 

 divisions and is fertile; the third segments are 55 in diameter. The 

 third node bears 4 divisions and is fertile ; the fourth segments are 40 

 to 45 in diameter, and taper to about 35 at the upper end of the penul- 

 timate cell. The terminals, 2 or 3 in number, are quite long and usu- 

 ally 3-celled ; they bear sometimes a fourth node, which is rarely fertile 

 and in turn carries 2 to 3 secondary terminals. The terminal cell, a 

 mucro, is about 25 in diameter at base and 60 to 65 long. 



The oogonia are isolated at the second and third nodes of the 

 leaves, the oospore 260 long by 220 broad (those seen were too imma- 

 ture to determine the character of the Nordstedt markings). Antheridia 

 180 in diam. 



Transitional forms between gracilis and tenuissima. 



Several collections have brought to light forms which, while very 

 similar to each other, cannot be referred either to gracilis or tenuissima. 

 Like the latter, the stems are usually tufted from one root and quite 

 simple. Like the former, the leaves are long and delicate, not divari- 

 cate, at times longer than the internode and overlapping the adjoining 

 verticil. The characteristics of specimens from four widely different 

 localities are so similar that I am persuaded, for the sake of convenience, 

 to give them a name. 



