See. MELANOSPERMEiE. ( 115 ) Fam. CHORDARIE.E. 



MESOGLOIA VIEESCENS.— C«rm. 



Gen. Char. — Frond gelatinous, filiform, subcylindrical, much and irregularly branched, 

 of two strata of cells ; those of the axis arranged in longitudinal filamentous 

 series ; those of the periphery forming vertical, dichotomous, moniliform series ; 

 those at the apices clustered, frequently club-shaped, simple, moniliform. Fructi- 

 fication : obovate spores attached near the base of the apical fibres. Name from 

 /ue'ffoy, "the middle," and y\oihs, "viscid," alluding to the very gelatinous nature 

 of the fronds. 



Mesogloia virescens. — Frond filiform, much branched ; branches 

 long, slender, nearly simple, or more frequently covered with numerous 

 short, simple, or forked ramuli, which are linear, obtuse, and very 

 patent. 



Mesogloia virescens. — Carm. Alg. Appin. ined. ; ffooJc. Br. Fl. vol. ii. p. 387 ; 

 Wyatt, Alg. Damn, No. 49 ; BerTc. Gl. Alg. t. 17, f. 2 ; Earv. P. B. 

 plate 82; Harv. Man. p. 47; Harv. Syn. p. 41; Atlas, plate 14, 

 fig. 57 ; Harv. N. B. A. part 1, p. 126 ; /. G. Agardh, Sp. Gen. Alg. 

 vol. i. p. 56. 



Mesogloia affiiiis. — Berk. Gl. Alg. t. 16, f. 2. 



Mesogloia Hornemanni, Suhr ? — Kiitz. Phyc. Gen. p. 332 ? 



Tricholadia virescens. — Harv. in Mach. Fl. H'lb. part 3, p. 184. 



Helminthocladia virescens. — Harv. Man. 1st edit. p. 46. 



Hab. — On stones, shells, rocks and Algse, at half-tide level. Annual. Spring. 

 Summer. Common. 



Geogr. Dist. — Northern shores of Europe ; Baltic Sea ; Atlantic coasts of France. 



Description. — Eoot, a minute disc. Fronds single or tufted, three 

 to eight inches or more in length, and scarcely half a line in diameter, 

 cylindrical, filiform, much branched from the base, middle branches 

 longest; branches long, slender, patent, scarcely tapering, generally 

 thickly covered with short, cylindrical, obtuse, veiy patent, mostly simple 

 ramuli, from an eighth to a quarter of an inch in length. The main 

 stem is generally percuiTcnt, but sometimes in luxuriant specimens it is 

 once or oftener divided in a subdichotomous manner, each division 

 resembling a primaiy, the long slender branches are often mixed with 

 short ones resembling the ramuli, those at the apex being also gradu- 

 ally but suddenly shortened, and a few at the base are sometimes also 

 abbreviated. Structure : the axis composed of cylindrical cells, airangcd 

 in longitudinal filiform series, from which arise numerous vertical, 

 dichotomous, moniliform filaments, forming the periphery. These 



