LYNGBY, 257 
“Mr. Cresswell states that it grows 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. fig. 2. uw, portion of fascicles of trichomes X 100; 4, tri- 
chomes X 400. 
Inactis tinctoria. Thur. Ann, Sct. Nat. (1875) 377. 
Fasciculate cespitose, 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 lamellose, even. 
Size. Trichomes :002 mm. diam. 
Hydrocoleum tinctorium, Br. Rabh. Alg. Eur, ii., 294. Ralfs 
Exs., No. 19. 
On aquatic plants. 
Mr. Marquand says that he has never seen it growing on any other 
plant than Scirpus 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. Inits 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. Ralfs :—‘‘ 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.”—Ra//s. 
Plate C. fig. 8. Upper portion of fascicle of trichomes X 400. 
Genus 104. LYNGBYA, dg. 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. 
