SIPHONACEJE. 
9 
Order L— SIPHONACEiE. 
Siphonece and Caulerpece , Grev. Alg. Brit. p. 183. J. Ag. Alg. Medit. p. 17. 
Endl. 3rd Suppl. p. 16. Dne. Class , p. 32; (also Haly medece, Dne.) Lindl. Veg. 
Kingd. p. IS, and Vaucheriece, in part, p. 22. Vaucheriece, Caulerpece , Codiece (in 
part), Kutz. Sp. Alg. pp. 486, 494, 500. 
Diagnosis. Green, marine or fresh water Algae, naked or coated with carbonate of 
lime, composed either of a single, filiform, branching cell, or of many such cells united 
together into a spongelike frond. 
Natural Character. Boot, where it is developed, formed of many branching 
fibres interwoven together and entangled ; sometimes penetrating deeply into the sand 
in which the plant grows, and attaching itself to the separate grains of sand, which 
serve further to consolidate the mass of fibres. Frond very variable in appearance, 
and differing much in complexity of structure, but always formed of very long, 
branching, inarticulate filaments, which arise from the continued growth and evolution 
of a single, undivided cell. In the genera of simplest structure, such as Bryopsis 
and Vaucheria, the frond consists of a single branching filamentous cell, with a thin, 
membranous, hyaline cell-wall ; its cavity being filled with a granular semifluid colour- 
ing matter or endochrome, which may be wholly discharged if the tube be wounded 
and slightly pressed. In Bryopsis the unicellular fronds stand apart from each other, 
though many often rise nearly from the same base. In Vaucheria several such fronds 
are interwoven together at the base, but remain distinct in their upper branches. In 
Chlorodesmis there is a further union of many such threads, whose lower portion 
unite together to form an evident stipes or trunk, which is crowned with a pencil of 
free filaments ; the whole frond resembling a little tree. This habit, however, is not 
so obvious in the American species as it is in Ch. comosa, the first described species of 
the genus. Again, in Codium, we find a structure essentially the same as in Vau- 
cheria and Chlorodesmis, but the union of the filaments is still more intimate. To 
the naked eye, the species of Codium resemble green sponges or pieces of green cloth 
or velvet, having a perfectly definite outline and closely interwoven substance, and it is 
only when we tear or cut them asunder under the microscope that we perceive their 
true structure. We then find that all the central part of the substance of the frond is 
composed of innumerable interwoven, longitudinal branching cells, and that the velvetty 
pile which constitutes the surface is formed of the tips of excurrent branches of the 
axial cells, lying close together and presenting only their extremities to the eye. In all 
