LYNGBY.E. 257 



" Mr. Cresswell states that it prows at the very top of high water mark, 

 in situations where it is exposed to the continual drip of fresh water 

 falling from high mural cliffs, and that it is most luxuriant where the 

 drip falls from the greatest height, which in the station observed is about 

 fifty feet." Harvey. 



Plate C. Jig. 2. a, portion of fascicles of trichomes X 100 ; b, tri- 

 chomes X 400. 



Inactis tinctoxia. Thur. Ann. Sci. Nat. (1875) 377. 



Fasciculate csespitose, dingy brown becoming olive ; trichomes 

 single or many associated in one sheath, joints equal in length 

 to their diameter or a little longer; sheaths broad, colourless, 

 distinctly lanaellose, even. 



SIZE. Trichomes '002 mm. diam. 



Hydrocoleum tinctorium, Br. Rabh. Alg. Ear. ii., 294. Ralfs 

 Exs., No. 19. 



On aquatic plants. 



Mr. Marquand says that he has never seen it growing on any other 

 plant than Scirpvs fluitans, .and he adds : " I have never seen a vestige 

 of green about it in its natural condition during any period of its exis- 

 tence ; when decaying it becomes pale, and eventually almost white ; 

 when in its best condition it is of a rich chesnut brown. In drying it 

 turns green. In its best condition, when placed in water for twelve hours, 

 it will dye it of a clear rosy purple." 



The following description of this plant has been kindly furnished by 

 Mr. Kalfs : " In rapid streams on leaves of aquatic plants, it forms a 

 minute continuous covering on leaves of aquatic grasses, giving them a 

 feathery appearance. Colour varying from nearly black to pale reddish 

 brown ; in drying and decay it turns green, and gives a purplish stain to 

 paper. Filaments somewhat mucous, very slender, nearly colourless, 

 cohering at base in fascicles containing 3 to 8 filaments, and by their 

 separation at intervals, simulate branches, and thus gradually reduce the 

 number cohering until they ultimately separate into single ones. The 

 filaments thus appear comparatively stout at the base and gradually to 

 become attenuated upwards. As the apparent branches are given off this 

 is more especially the case, because, from their pale colour, indistinct 

 endochrome, and closeness of connection, it requires care to detect that 

 they are really fascicled. Besides the elongated filaments there are 

 numerous short ones at the base, together with crowded, somewhat 

 thicker clavate erect bodies. Whether these are the fructification or 

 rudimentary fascicles I am unable to determine." Ralfs. 



Plate C.fig. 3. Upper portion of fascicle of trichomes X 400. 



GENUS 104. LYNGBYA, Ag. em. Thuret. (1875.) 



Filaments enclosed singly in a sheath, simple, or only excep- 

 tionally exhibiting the beginning of ramification where the 

 trichome issues from the side of the sheath ; often combined in 

 a membranaceous stratum. including Phormidium Kutz. 



