44 SYNOPSIS OF BRITISIT SEAWEEDS. 



rising from a scarcely perceptible tubercle. As it grows 

 larger, the colour changes to brown, and the tubercle in- 

 creases much in size, and at Length becomes a button, at- 

 tached by a central point. It then (nils away and the 

 plant perishes. The growth of other "Elaehista is very 

 similar. By J. Agardli this genus is placed with the JScto- 

 carpetc, but in my opinion incorrectly. 



60. flaccida (The flaccid Elachista) ; tufts pencilled : filaments 

 elongate, flaccid, membranaceous, much attenuated to the 

 base ; the lower articulations half as long as broad, the 

 upper of equal length and breadth ; tubercle hemispherical, 

 Aresch. (Atlas, PL XV. Fig. 62.) 



Elacliista breviarticulata, Aresch. Phycophila flaccida, Ktz. 

 Myrionema breviarticulatum, JSndl. Conferva flaccida, 

 Dillw. C. obtusa, Ag. C. breviarticulata, Suhr. 

 Hab. Atlantic coasts of England. Parasitical on Cystoseira 

 fibrosa, common. Annual. Summer and autumn. 

 A very common parasite on Cystoseira fibrosa, whoso 

 branches are rarely found free from the olive-coloured sof< 

 pencils of this little plant. In size and appearance to the 

 naked eye there is much resemblance to preceding species, 

 except that the colour is generally greener, and the length 

 of the tufts rather less ; but under the microscope these 

 species are very readily known from one another. JE. flac- 

 cida is remarkable for the shortness of its articulations, in 

 proportion to their breadth throughout the lower and 

 middle portions of the filaments, and for the gradually 

 increasing length of the cells towards the apices. The 

 filaments, also, taper exceedingly at the base ; and the 

 tubercle from which they originate is of very much smaller 

 size than in E.fucicola. 



61. curta (The short Elachista) ; filaments very short, tapering 

 to the base, obtuse, pencilled, rather rigid, rising from a 

 tubercle ; articulations about as long as broad ; spores pyri- 

 form, on long pedicels ; paranemata linear-clavate, Aresch. in 

 Linn. v. 16. p. 234 ? (Atlas, PL XV. Fig. 63.) 



Conferva curta, Dillw. 



Sab. Swansea. On Fuci, between tide-marks. Annual. Summer. 

 This species has long been in doubt, and notwith- 

 standing the figure and description now r given, my doubts 

 are not fully removed. By Dillwyn, who first described 

 E. curta, it is said to be common in the neighbourhood of 

 Swansea, and probably not rare elsewhere; yet no one 



