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MELANOSPERME®. 71 
paper and allowed to dry or shrink a little ; then-upon immersing it in sea- 
water again, and afterwards draining away the water, it may be treated in 
the ordinary way, always bearing in mind that pressure for fleshy as well 
as gelatinous plants, must be gradually and carefully applied. 
The genus Ralfsic, named in honour of John Ralfs, Esq., of Penzance, 
contains one species only, Ralfsia verrucosa, the frond of which is of a 
leathery or crustaceous nature. It is attached by its under surface to the 
flat rocks which occur in some situations between tide-marks. The colour 
of this leathery-like plant is a dull brown. The fruit is contained in 
dwarf-like prou,inences, which appear on the surface of the plant, scattered 
here and there among the con- 
centric zone-like markings of 
the fronds. 
The genus Elachista — from 
the Greek, signifying ‘‘the 
least,’’ in reference to the small 
size of these plants—contains 
several species, all of which, 
with the exception of one, are 
more interesting as objects for 
microscopic examination than 
as specimens for ordinary collec- 
tions. The largest and com- 
monest of these tiny plants is 
the species Elachista fucicola 
(Fig. 73), which is found con- 
stantly parasitical near the 
terminal branches of Fucus 
vesiculosus (Fig. 37). Four tufts 
of this parasite are represented 
growing on the Fucus (a), and 
under it (b) a branch of the 
eclub-headed jointed filaments 
which arise from the tubercular 
base, among which the pear- 
Fie. 73 (a) Elachista fucieola on Fucus vesi- shaped spores of these minute 
ee ae a filament with spore, plants are produced. The tufts 
of this Elachista are rarely 
more than an inch long, and are of a dark olive colour. F. pulvinata, 
or attenuata, is parasitical on Cystoseira ericoides. Fig. 74 represents 
a terminal branch of the Cystoseira, on which are growing several little 
globular or cushion-life tufts of this minute parasite. An examination 
of this figure, which was carefully taken from the living plant, will help 
students to recognise this species, as well as to give them a general idea 
of the appearance and manner of growth of other species of Elachiste. 
E. stellulata, a minute star-like plant, parasitic on Dictyota dichotoma 
