numerous pores communicating with the immersed conc^tacles or spore-
chambers. These latter are spherical, and contain numerous oblong, simple,
dark-brown spores, mixed with tufts of branching filaments bearing bright
orange antheridia. Colour, when young, a greenish olive, in age becoming
a rich brown. Substance veiy tough and leathery. •
One of the handsomest of the British Fucea and common on
all our shores. It is subject to little variation, except in size.
When growing in shallow water, or in tide pools near high water
mark, it becomes stunted in its habit, having the branches more
closely set, and bushy, and every part proportionably smaller and
narrower. This state constitutes the var. /3. of authors.
The genus Halidrys, founded by Lyngbye, is well distinguished
from all other Fticece by tbe curious structure of its air-vessels.
These compound au’-vessels are confined to tbe present individual,
and to tbe beautiful Fucus osnmndaceus of Turner, a native of tbe
West coast of North America. In this latter species the structure
is sbghtly diiferent, and the vesicles are much constricted at
the joints, like strings of beads. The whole habit, however, is so
very similar to that of our H. siliquosa, that I cannot but consider
it as properly a member of tbe same natural genus.
Kg. 1. H.4LIDBYS smaxJOSA ; Portion of a brandi -.— the natural size. 2. Longitudinal
section of an air-vessel. 3. Transverse section of a receptacle,
with its immersed conceptacles, containing spores and antheridia. 4. Spores ;
— all more or le ’