IV. 
SPOROCHNACEiE. 
73 
Order II -SPOEOCHNACE^. 
Harv. Man. Br. Alg. Ed. 2, p. 21. Sporochnoidece, Grev. Alg. Brit. p. 36. J. Ag. 
Sp. Alg. vol. 1, p. 160. Kiitz. Phyc. Gen. p. 342. Kutz. Sp. Alg. p. 567. Endl. 
3rd. Suppl. p. 28. Cliordariece, in part Ag. Syst.p. xxxvi. Sporochnidece and part of 
Dictyotidce , Lindl. Veg. Kingd. p. 22. 
Diagnosis. Olive-coloured, inarticulate seaweeds, whose spores are attached to 
external, jointed filaments, which are either free or compacted together into knob- 
iike masses. ( Plants of mediocre size, soon becoming flaccid in the air , and then chang- 
ing to a verdigris-green colour). 
Natural Character. Root usually a small, naked disc or point of attachment ; 
in Carpomitra, bulbous and coated with woolly threads. Fronds of mediocre size, 
and much branched, frequently bushy, having, whilst living, a clear and rather 
bright brownish olive or chestnut colour, and a cartilaginous, firm, crisp substance ; 
but rapidly becoming flaccid and changing to a verdigris green colour on exposure 
to the air, and possessing, after this change, the faculty of rapidly decomposing any 
small Alga; with which they may come in contact. Stems and branches uniform, 
destitute of any separate, leaf-like expansions, inarticulate ; sometimes cylindrical 
and filiform, often exceedingly slender ; sometimes compressed ; and sometimes 
flattened, leaf-like, and furnished with a distinct midrib, occasionally throwing off 
lateral nervelets. The branching is frequently opposite, and almost always disti- 
chous. Air-vessels none. Almost all bear, at some period of their growth, pencils 
of delicate, jointed, confervoid filaments. In some, as in Pesmarestia and Arthro- 
cladia , these filaments are found on the growing apices, and on all the younger 
portions of the frond, and appear to be intimately connected with the process of 
cell-division then going on ; and they gradually fall away after the part has attained 
its full size. In Arthrocladia a portion of them remains, and eventually supports 
the fructification. In others, as in Sporochnus and Carpomitra , similar filaments 
spring from and crown the receptacles of the fructification, and fall array when the 
spores have arrived at maturity. 
The outward appearance of the fructification varies in the different genera of this 
Order, but the differences are of a minor character. In all, the spores are attached 
to branching, articulated filaments which issue from some part of the branches, 
and are, therefore, external to the substance. But in some, as in all the American 
genera, these filaments are free, either clothing the branches or forming pencil-like 
VOL, HI. ART. 4. L 
