64 BRITISH MARINE ALG. 
produced on various parts of the tubular fronds, scattered singly or 
sometimes in pairs. In eariy summer this little thread-like plant 
dries a brilliant green; but in the mature state, as represented in our 
illustration, the endochrome of the cells having decayed or perished, the 
fronds turn to a brownish olive. The most effective manner of mounting 
this species on paper, is to cut a longitudinal slice of the Chorda, 
and place the cut side on the paper, takinz care to spread out the 
fronds of the parasite while they are still floating in the water, 
which must be drained away gradually, raising one side of the paper 
at a time, or the limp fronds of the plant will either clot together or 
arrange themselves in an unnatural position. Litosiphon laminariee, is 
an extremely minute parasite, whose place of growth is on the lamina or 
leafy part of Alama esculenta (Fig.50). It consists of little starlike tufts 
rarely an inch in length, and is scattered thus at very short distances apart, 
sometimes over the whole extent of the fronds of the Alaria. This little 
parasite being almost microscopic, is, as regards its fructification, com- 
pletely so. ‘The cellular structure of its tiny fronds is extremely beau- 
tiful though very simple. The cells are arranged in transverse bands 
placed very close together; and within these bands of cells the spores 
are produced. ; 
The genus Asperococcus is named from the Latin and Greek, signifying 
rough fruit or seed ; the spots of fructification, which are thickly scattered 
over both surfaces of the fronds of these plants, causing them to feel 
harsh or rough to the touch. They all vary in size according to the 
depth of water in which they grow. Fig. 68, represents a group of fronds 
of Asperococcus compressus, one of the rarest of this genus. This species is 
a summer annual. It is rarely found growing, being a deep water plant. 
[ have taken it only in the neignbourhood of Plymouth. The fronds are 
from 6in. to about 20in. long. They are tubular but compressed or 
flattened at the sides, hence the specific name. The colour of this species 
is more inclined to a greenish tint than any other of the genus to which 
it belongs, and in drying, it invariably turns to a pale green, thus 
throwing out in strong relief the numerous oblong sori or spots of fructi- 
fication. ‘The flat growth of this plant renders it easily manageable in 
preparing it for the herbarium, and it closely adheres to paper in drying. 
A. Turnert is also rare. It is sometimes found in rock pools, but more 
frequently, with the help of the dredge, in sheltered bays, in five to fifteen 
fathoms. The fronds of this species vary in length from 4in. to nearly 
as many feet, the largest being obtained in deep water. They are like 
long inflated bags, constricted here and there at irregular intervals, and 
taper very suddenly at the base into a short stem, being attached to 
rocks or stones by a very minute naked disk. The colour is pale olive, 
becoming darker in drying, a character which is probably due to the 
minute dots of fruit, which are densely scattered over the whole surface 
ot the fronds. A. echinatus, Fig, 69, is the commonest of its tribe. It 
varies in size, like the others of this genus, but the ordinary length its 
