Fig. 253. GRIFFITHSIA SETACEA. 
Colour. A bright transparent crimson ; which is given out very soon in fresh water. 
Substance. Remarkably crisp and firm when fresh ; soon becoming flabby and soft on exposure. 
Character of Frond. Tufts of distinctly marked, jointed threads {filaments), forming a more 
or less rounded outline. Filaments as thick as hogs’ bristles ; very straight ; 
irregularly forked ; angles of branching {axils) narrow ; lesser branches sometimes 
opposite ; occasionally throwing out below a few root-lil?:e fibres, which connect the 
filaments together. 
Measurement. From 3 to 6 inches long. 
Fructification. Of two kinds. Minute spores in stalked, mostly double, capsules; surrounded 
by enfolding branchletee/is. 2. Tetraspores crowded on the inner sides of special 
enfolding branchletee/zs. 
Habitat. Our shores generally. On rocks, &c. between tide-marks under the shade of large 
algas. Common. 
Fig. 254. CALLITHAMNION PLUMULA. 
Colour. A beautiful rose-red. 
Substance. Delicately soft and tender. 
Character of Frond. Tufts of jointed threads {filaments) very much branched. Stems un- 
divided or somewhat forked ; furnished with alternate or irregular slender branches ; 
the upper ones longest and most divided ; all the divisions and branches at one level 
{distichous) ; every joint bearing a pair of short, horizontal, or back-curved, exactly 
opposite branchlets, whose upper margin is clothed with a second set ; these some- 
times with a third ; all regularly set like the teeth of small combs {pectinated). 
Joints. Visible throughout (when examined through the microscope). 
Measurement. From 2 to 5 inches long. 
Fructification. Of two kinds. 1. Minute spores in large, dark-red, double ; sessile 
on the main branches. 2. Minute, globose tetraspores borne on the tips of the 
then shortened branchleteews. 
Habitat. Our coasts from Orkney to Devon, but in the warmer stations. Dublin, &c. On 
rocks, &c. near low-water mark. Not uncommon. 
Fig. 255. CALLITHAMNION CRUCIATUM. 
Colour. A brownish-red ; soon fading to yellowish. 
Substance. Soft and flaccid (limp). 
Character of Frond. Dense tufts of jointed threads {filaments) ; branched, but rather sparingly. 
Stems irregularly divided into, or furnished with, a number of long, almost simple 
branches, which are sometimes re-branched. Each joint throughout, clothed with 
one or sometimes two pairs of slender, upright, sometimes simple, oftener re- 
branched, branchleteews. These so crowded at the tips that they present a darkened 
appearance, like the eye in a peacock’s tail. 
Joints. Visible throughout (under the microscope). 
Measurement. From 1 to 2 inches long. 
Fructification. Only one kind known. Tetraspores, dark-red, sessile on the (then) shortened 
branchletee?zs. 
Habitat. South of England and south and west of Ireland. On mud-covered rocks near low- 
water mark. Rare. 
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