Ser. MelanospeemejE. Fain. Ectocarpea. 



Plate CLXXXIII. 



ECTOCARPUS AMPHIBIUS, Haw. 



Gen. Char. Frond capillary, jointed, olive or brown, flaccid, single-tubed. 

 Fruit either spherical, elliptical, or lanceolate utricles (or spores) 

 borne on the ramuli, or imbedded in their substance. Ectocarpus 

 (Lpigb.), — from cktos, external, and Kapnos, fruit. 



Ectocarpus amphibius \ tufts short, loose, soft, pale olive; filaments very 

 slender, subdichotomous ; ultimate branches alternate, spreading j 

 articulations two or three times longer than broad ; utricles (?) linear- 

 attenuate, spine-like, mostly sessile, scattered. 

 Ectocarpus amphibius, Harv. Phyc. vol. i. p. x. 



Hab. In muddy ditches of brackish water, near the coast. Tide ditches, 

 communicating with the Avon, below Bristol. Mr. G. II K. Tkwaites. 

 Geogr. Distr. 



Descr. Filaments 2-3 inches long, very slender, flaccid, forming small, indefi- 

 nite tufts, growing on the mud, or attached to various substances, vaguely 

 branched in a manner between dichotomous and alternate ; the lesser divi- 

 sions mostly alternate, erecto-patent, not much divided, nor remarkably 

 attenuate. Ramuli scattered, thorn-like, at length frecpiently changed into 

 exceedingly long, sessile, opake, sporaceous bodies, evidently analogous to 

 the utricle of Ectocarpus siliculosus, and of a character intermediate between 

 these and the immersed fructification of E. littoralis. Articulations of the 

 main branches twice or thrice as long as broad, pale olive, pellucid, mostly 

 marked w r ith a few irregular bands of more solid endochrome. Colour 

 fading in the Herbarium, and becoming greener. In drying, it closely 

 adheres to paper. 



The occurrence of an Ectocarpus in brackish water, though not 

 without precedent, deserves to be recorded, and it is more on 

 that account, than because I am certain of the present plant being 

 a good species, that I give it a place in this work. It will be 

 seen that its characters border very closely on those of E. silicu- 

 losas, from which the usually sessile fructification and the attenu- 

 ated form of this part chiefly distinguish it. The resemblance is 

 so striking that one is almost disposed to the belief that our A'. 

 amphibius may be only E. sUicuhsm altered by growing in water 

 which contains a very small quantity of salt. Mv. Thwaites, to 

 whom I am indebted for a beautifully mounted specimen, and 

 who also had the kindness to communicate fresh specimens, 



VOL. II. U 



