(190) 



the lower axils acute, the divisions erecto-patent, and the articulations 

 very long and cylindiical, in old plants those at the base frequently 

 more or less filled with slender articulated filaments. Substance very 

 tender and gelatinous, and closely adhering to the paper in drying. 

 Colour, a fine rosy red or pink when fresh, soon changing in fresh water 

 to an orange or pale brown. FaveUse " generally in pairs, terminating 

 the secondary branches, and sometimes surrounded by a few forked 

 ramuli." Tetraspores spherical, sessile, opposite or a little below the 

 axils of the upper ramuli. 



The present by no means uncommon species includes what has by 

 many been considered two species, G. cori/mhosum and C. versicolor, two 

 species which seem much too nearly allied for separation, when both 

 species are acknowledged to be of such variable character, and especially 

 when the differences are only of secondary importance. 



The species seems pretty generally distributed, and is frequent in 

 sheltered bays, estuaries, and places where the water is slightly brackish, 

 on the leaves of Zostera marina, and other marine plants, as well as on 

 rocks and stones, especially in a rather muddy bottom. 



Its newest ally is said to be G. spongiosum, but that may be at once 

 distinguished by its shorter articulations, much more densely bush habit, 

 much stouter stems, more tapering to the apices, which are less obtuse 

 and rather more slender. It does not seem abundant on the east coast, 

 but we have gathered it but sparingly in widely distant localities j both 

 kinds of fruit seem to be not uncommon. 



EXPLANATION OF PLATE CXXVIIL 



Fig. 1. — Callithamnion corymhosum, natural size. 

 2. — Ramulus with tetraspores. 

 3. — Ramulus with favellas. 

 4. — Articulation. All magnified. 



