Fig. 193. GRACILARIA COMPRESSA. 
Colour. A transparent dull red ; becoming brighter in fresh water. 
Substance. Very tender and brittle ; succulent ; somewhat gelatinous. 
Character of Frond. Tufts of cylindrical, or somewhat compressed stems, which are either 
undivided and alternately branched from the base, or partly forked at first ; alternately 
branched afterwards. Branches long, and mostly simple ; tapering to a fine point ; 
occasionally furnished with branchlets. 
Measurement. From 6 to 12 inches long. 
Fructification. Of two kinds. 1. A mass of spores in almost conical capsules ; external ; 
sessile on the branches. 2. Tetraspores minute ; imbedded in the same. 
Habitat. South of England. Cast ashore from deep water. Very rare. 
Fig. 194. GIGARTINA MAMILLOSA. 
Colour. A dark purple. 
Substance. Gristly ; tough ; elastic. 
Character of Frond. Tufts of, first cylindrical, then flat stems, becoming channelled or 
grooved upwards, and widening into wedge-shaped, irregularly forked {dichotomous) 
divisions, or branches. Divisions channelled ; more or less broadly wedge-shaped ; 
often forked at the tips ; the angles acute ; their surface and margins dotted over 
with minute, short, thick, stalked frondlets, in which the capsular fruit is formed. 
Measurement. From 3 to 6 inches high. Width of the divisions varying greatly in different 
specimens. 
Fructification. Only one kind observed. A mass of spores in globose capsules ; formed on 
the frondlets. 
Habitat. Our coasts generally. On rocks, &c. near low-water mark. Common. 
For other Gigartinas see Plate XLIII. Fig. 197 ; Plate XLIV. Fig. 201 ; and Plate L. Fig. 225. 
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