two or three small processes above ; sometimes compounded in the manner 
of a Greek cross. Capsules formed near the tips of the ramuli, but rarely 
perfect ; more commonly converted into cup-shaped bodies. Tetraspores 
densely imbedded in the tips of the ramuli. Colour a fugitive pink, the 
main branches, and sometimes the whole frond, yellowish or transparent ; 
the ramuli more fully coloured. Swdstance cartilaginous, tender and brittle, 
soon decaying in fresh water; closely adhering to paper in drying. 
DORR eee 
This species is as widely dispersed over the world as Z. pin- 
natifida, and though not quite so variable as that plant in general 
appearance, nevertheless exhibits considerable varieties. ‘This is 
to be expected in a plant which grows as well in subtropical as 
in temperate waters ; and which even extends within the tropics. 
On our shores, except in colour, it preserves most of the characters 
represented in the plate; but continental specimens are often 
much taller in proportion to their breadth, till the pyramidal 
outline becomes almost as long, in proportion to its base, as an 
obelisc. When growing in sunny pools the whole plant often 
becomes pale yellow, preserving merely in the youngest ramuli 
a rosy hue; but in deeper water, and under the shade of leafy 
Algze, all the branches are of a full red. 
I believe that Laurencia obtusa is always, or, at least, very 
generally, a parasite on other Algze; but it appears to be quite 
indifferent as to the species on which it grows. I have seen it 
on several plants of very different natures. Most commonly it is 
found on Fucus serratus, or on Corallina officinalis: but it also 
grows on Chondrus crispus, Polysiphonia nigrescens, and even on 
Sphacelarva cirrhosa. 
‘letraspores are abundantly produced; but capsules I have 
rarely found perfect on British specimens. It is more usual to 
find the tips of the ramuli converted into those cup-shaped, open 
bodies, contaming yellow flocculi, which are represented in our 
plate of L. pinnatifida. 
— 
=F) 
. LAURENCIA OBTUSA; growing on Fucus serratus :—of the natural size. 
. Branch with capsules. 3. A capsule. 4. Tuft of spores from the same. 
Branch with tetraspores. 6. A tetraspore :—all magnified. 
JQ” 
onwr 
