Ser. Melanosperme.e. Tarn. Ectocarpea. 



Plate CLVI. 



MYRIOTRICHIA FIL1FORMIS, Haw. 



Gen. Char. Fronds capillary, flaccid, jointed, (simple) beset with quadri- 

 farious, simple, spine-like ramuli, clothed with byssoid fibres. Fructi- 

 fication ; ellipticle utricles (or spores) containing a dark-coloured mass. 

 Myriotrichia (Harv.), — from nvpios, a thousand, and 0pi£, sl hair. 



M.YBl(yrBlGHLi.filiformis; stem filiform, slender, often flexuous or curled, 



beset at irregular intervals with oblong clusters of short, papillaeform 



ramuli. 

 Myriotrichia filiformis, Hare. Man. p. 44. Wyatt, Alg. Damn. no. 213. 

 Hab. Parasitical on Chorda lomeutaria, often accompanying M. clava- 



forrnis. Annual. Summer. Not uncommon on the English and 



Irish shores. 



Geogr. Distr. British Islands. 



Descr. Fronds an inch or more in length, very slender, densely clothing the 

 fronds of Chorda lomentaria, tufted, flexuous, simple, filiform, at intervals 

 appearing thickened or knobbed ; the knobbed portions formed of exceedingly 

 dense, short, papillseform ramuli. Both the ramuli and the main stems 

 emit numerous, long, simple, colourless, byssoid fibres. Articulations 

 shorter than broad, filled with dense, granular matter. Spores spherical, 

 with a hyaline pericarp, variously scattered along the main filament. Colour 

 varying from a yellowish olive to a pale brown. Substance tender, and 

 more or less gelatinous, closely adhering to paper, and usually gloasy when 

 dry. 



A comparison of the figure here given, with that of M. clava- 

 formis at Plate CI., will best show the differences between these 

 two plants. It will be seen that while in the former the ramuli 

 regularly increase in length from the base upwards so as to give 

 the frond a club-shaped, or very slender pear-shaped outline ; in 

 this they preserve nearly an equal length in different parts of the 

 frond, and are collected into oblong clusters, separated by spaces 

 bare of ramuli. In all other respects the two plants closely 

 resemble each other, and as they are frequently found intermixed 

 on the same frond of Chorda lomentaria, 1 formerly regarded the' 

 present as merely a state of M. davaformis. The merit of 

 having correctly distinguished these closely allied species is due 

 to Mrs. Griffiths, who first pointed out the peculiar characters 

 of both. 



