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. Substance cartilaginous, tender and brittle,
soon decaying in fresh water ; closely adhering to paper in drying.
This species is as wideiy dispersed over the world as L. 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
obelise. When growing in sunny pools the whole plant often
becomes pale yellow, preserving merely in the youngest ramuli
a rosy hue; hut in deeper water, and under the shade of leafy
Algae, all the branches are of a full red.
I believe that Laurencia obtusa is always, or, at least, very
generally, a parasite on other Algae; 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 niyrescens, and even on
Sphacelaria cirrhosa.
Tetraspores 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.
: 111
i i i
Fig. 1. L a t o e n o ia OBTUSA; growing on Eacus serratus-.— of the natural size.
2. Brancli with capsules. 3. A capsule. 4. Tuft of spores from the same.
5. Branch with tetraspores. 6. A tetraspore:— a lii