Plate LIIL 
Fig. 242. CERAMIUM RUBRUM. 
Colour. Sometimes clear red, sometimes darker ; brownish-yellow and white in decay ; on 
examination, of different shades. 
Substance. Firm when fresh ; soon turning flabby ; giving out a pleasant smell. 
Character of Frond. Tufts of jointed threads {filaments). Filaments sometimes coarse, some- 
times slender ; becoming finer upwards from the base ; much and irregularly branched 
in a partly forked, partly alternate manner ; set throughout more or less with once- 
forked, or many-times-divided, often secund branchlets. Tips hooked in. 
Joints. Coloured throughout red, but in different shades. Darkest at, and near, the partition- 
lines {dissepiments) j which are always slightly contracted, and in drying often shrink 
considerably. 
Measurement. From 2 to 12 inches long. 
Fructification. Of two kinds. 1. Minute spores in globose capsules^ with two or three short, 
curved branchleteews underneath ; mostly borne on the side-branchlets. 2. Tetra- 
spores set round the joints. 
Habitat. Our coasts generally. In pools from high to low-water mark, and beyond. Very 
common. 
No description can include all the varieties of this most variable plant, but whether dark 
or pale, bright or dingy, it is coloured throughout, though in shades ; and as there is but one 
other un-thorned British Ceramhim {C. hotryocarpum) in which this is the case, the detection 
of delusive varieties is not so difficult as may be thought. From C. hoiryocarpimi it differs 
entirely in its capsular fruit. 
Fig. 243. CEEAMIUM BOTRYOCARPUM. 
Colour. A dull purplish-red, fading to green and yellow ; on examination, of different shades. 
Substance. Rigid. 
Character of Frond. Tufts of jointed threads {filaments). Filaments crooked at the base ; 
rather coarse ; becoming gradually finer upwards ; much and irregularly branched ; 
in a sometimes forked, sometimes alternate manner ; closely set with numerous short, 
simple, or once or twice divided branchlets. Tips straight. 
Joints. Coloured throughout dull purplish-red, but in difierent shades. Darkest at, and near, 
the partition-lines {dissepiments) ^ which are always slightly contracted, and in drying 
shrink considerably. 
Measw'ement. From 2 to 6 inches long. 
Fructfication. Of two kinds, but only one thoroughly made out. Tetraspores set round the 
joints. The other consists of minute dark fruit-warts heaped together in roundish 
clusters ; sessile on the branchlets. Occasionally a true capsule, with two or three 
branchletee?2S underneath, has been met with. 
Habitat. Our coasts generally. On rocks, &c. between tide-marks. Common. 
Besides the clumsy and unusual fruit, this plant is darker than C. ruhrim, and more 
purple. Moreover, the tips of all the branchlets are straight, instead of hooked in. 
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