76 CALLITHAMNE^. 



has since added it to the British flora, having found it at 

 Winterbourne Stream at Lewes, Sussex ; and to him and 

 Mr. Turner I am indebted for the specimen here figured. 

 It grows on flint stones in little tufts about a quarter of an 

 inch in length, and of a bluish green colour, glossy when 

 dry. The filaments, which are repeatedly branched, are 

 erect, straight, of equal height, and very flaccid and slender 

 throughout. The branches are placed at uncertain, gene- 

 rally considerable distances, from each other, and issue from 

 the stem so as to produce an obtuse angle, but immediately 

 curve inwards, and then rise in a more or less upright direc- 

 tion ; their disposition is far from regular, but they are fre- 

 quently disposed on opposite sides in alternate parcels of 

 two or three. The ramuli are always placed nearer to each 

 other than the main branches, and I have frequently ob- 

 served more than one proceeding from the top of the sanrj 

 joint ; they are blunt at their apices ; the dissepiments are 

 readily observable with a microscope, and divide the filaments 

 into perfectly cylindrical joints, of which the length is gene- 

 rally from four to six times greater than the diameter." 

 Dillw. 



To the above very accurate description of a most beautiful 

 production, it is necessary to add but very few words. The 

 single species of the genus Trentepohlia, like those of the 

 two preceding genera, seem to find pleasure in pure and 

 running waters, attaching itself to any substance favourably 

 placed in the current of the stream, and to which it can 

 firmly adhere. When in health the plant is of a blood-red 

 colour, a colour which, in decomposition, it readily imparts 

 to whatever it may be in contact with. This colour, how- 

 ever, is observed to change either by age or habitat, or 

 some other circumstance connected with its place of growth, 

 to a bluish grey, in which state it constitutes the Conferva 

 chalybea of Dr. Roth and Mr. Dillwyn. No difference can 

 be detected between the filaments of the two states, which 

 may therefore be concluded to be merely conditions of the 

 same Alga. The fructification, which adds much to the 

 beauty and elegance of the plant, is by no means rare. 



