14 BRITISH MARINE ALGA. 
mode of growth is most general among the Conferve proper, which are all 
unbranched. Recourse to the microscope is necessary for an examination 
of their structure, and also to identify species. These simple plants 
are propagated by zoospores, which 
are formed from the granular con- 
tents of the cells, or from the whole 
mass of endochrome or colouring 
matter of one or more cells being 
concentrated into an enlarged cell 
and forming there a sporangium or 
Spore - bearing conceptacle, from 
which, on the perishing of the old 
plant, new individuals are propa- 
gated. Fig. 10 represents a por- 
tion of a filament, highly magnified, 
of Conferva Youngana, the central 
joint of which contains a binate 
Sporangium. Fig. 11 represents 
portions of two filaments of the 
same species, highly magnified. 
Most of the Conferve inhabit 
fresh water, and are found abun- 
dantly wherever stagnant water 
lies, the oxygen which they continually throw off into the air, helping 
to neutralize the noxious effects which would otherwise arise from decaying 
vegetation in the water beneath them. The marine species of Conferva are 
not now very numerous ; one of the most common perhaps is Conferva 
tortuosa, well represented in the illustration (Fig. 12), a magnified filament 
of which was engraved on p. 5 (Fig. 1). This species is mostly parasitic 
on old stems of the Fuci, near high water mark ; but the masses of its 
entangled tortuous filaments are so inextricably interwoven, that it is 
useless attempting to separate them. The name Conferva is from the 
Latin Conferrwminare, to consolidate, the ancients having made use of 
masses of these plants in binding up wounds and fractured limbs. 
Among the Conferve there are two species by no means uncommon, 
which at a cursory glance strongly resemble each other, especially when 
they are seen growing in the water. One of them, Conferva wrea, is found 
on sand-covered rocks about half-tide level, growing in a tuft of erect 
filaments from 3in. to 4in. in length. The articulations or joints of the 
filaments are about as long as broad, and the whole plant, though harsh 
to the touch, loses its rigidity, and lies prostrate as the tide recedes from 
it. A plant of Conferva wrea is shown in (a) Fig. 124, and beside it a 
fragment of a filament magnified to show the form of the cells. The other 
species (b) is Conferva melagonium. It is usually found in rocky tide 
pools, where its long bristle-like filaments, from 4in. to 12in. in height, 
stand erect, stiff, and straight, even when left uncovered by the ebb of the 
Fig. 12. Conferva tortuosa. 
