Plate LX. 
Fig. 278. CALLITHAMNION ROTHII. 
Colour. Deep red or purple. 
Substance. Soft and velvety. 
Character of Frond. Dense tufts of very short, fine, jointed threads {filaments) ; forming 
velvety patches on rocks. Filaments very slender ; of one thickness throughout, 
slightly forked, irregularly branched. Branches very upright, rod-like ; the upper 
ones sometimes set with a few secund simple or branched branchlets, on some of 
which the tetraspores are borne. Tips pointed. 
Joints. Visible throughout. 
Measurement. From J to 1 inch high. 
Fructification. Only one kind known. Small round tetraspores^ often clustered together, borne 
on the (then) shortened end-branchlets. 
Habitat. Our coasts generally. Spreadingover the surface of rocks at half-tide level. Common. 
Fig. 279. CALLITHAMNION MESOCAEPUM. 
Colour. Purplish-red. 
Substance. Soft, velvety. 
Character of Frond. Tufts of minute, jointed threads forming a broad, shaggy, 
purple crust on the rock. Filaments rising from creeping fibres, upright, simple or 
sparingly branched. Branches alternate, very upright ; naked, or bearing a few little 
upright, often secund branchlets, on some of which the tetraspores are borne. 
Joints. Visible throughout. 
Measurement. One-fourth or ^ of an inch high. 
Fructification. Only one kind known. Oval tetraspores borne on the (then) shortened branch- 
lets ; often two on a branchlet. 
Habitat. Appin.^ On rocks at low-water mark. 
Fig. 280. CALLITHAMNION SPAESUM. 
Colour. Purplish-red. 
Substance. Soft, velvety. 
Character of Frond. Very minute, scattered tufts of fine, jointed threads {filaments). ^ Fila- 
ments nearly simple, upright, slightly branched upw^ards. Branches spreading ; of 
unequal lengths, alternate or secund; the tips blunt. 
Joints. Visible throughout. 
Measurement. Scarcely -Jg- of an inch high. 
Fructification, Only one kind known. Bluntly oval tetraspores ; sessile generally in the angles 
of branching {axils). 
Habitat. Appin. Miltown Malbay. On old stems of Laminaria saccharina, and on Cladophora 
rupestris. 
Very little observed, owing to its minuteness ; but not uncommon. 
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