SPOKOCHNACE^. 21 



appearance. This last commences the second year, rapidly attains its 

 full size, forms its frnit, and falls off at the end of the season. I have 

 never observed the old fronds to sprout again, but Carmichael asserts that 

 they do so. 



Ordek II. SPOROCHNACE^. 



Sporochnoideae, Gi'ev. Brit. Alg. p. 36. J. Jg. Sp. Alg. 

 vol. i. p. 160. Kutz. Phyc. Gen. p. 342. Endl. ^rd Siippl. 

 p. 28. Chordarieae, in part. Ag. Syst. p. xxxvi. Sporocli- 

 nidae, and part of Dictyotidae, Lindl. Veg. King. p. 22. 



Diagnosis. — Olive-coloured, inarticulate sea-weeds, whose 

 spores are attached to external, jointed filaments, which are 

 either free or compacted together into knob- like masses. 



Natural Character. — Root usually a small, scutate disk, 

 rarely bulbous, and coated with woolly fibres. Fronds, when 

 living, usually of a clear and rather bright olive colour, and 

 cartilaginous, firm substance, rapidly becoming flaccid and 

 changing to a verdigris-green colour in the air ; of mediocre 

 size and much branched, frequently bushy. Stems and 

 branches uniform, destitute of distinct leaves, inarticulate, 

 either cylindrical and filiform, often exceedingly slender, or 

 more or less compressed ; sometimes flattened, leaf-like, and 

 furnished with a distinct midrib, and occasionally lateral 

 nervelets ; the branches very frequently opposite, and almost 

 always distichous. Air-vessels none. Almost all bear, at some 

 period of their growth, pencils of delicate, jointed, confervoid 

 filaments. In some these accompany vegetation, sprouting 

 out from all the growing apices, and continuing while the 

 branchlet is in active growth, after which they fall away : 

 such may possibly discharge the office of leaves in these 

 leafless plants. In other kinds the filaments spring from 

 and crown the receptacles of the fructification, falling away, 

 in like manner, when the spores arrive at maturity. The ox- 

 gsius oi Jriictijication are varied considerably in this order. 

 In some the spores are developed on the pencilled filaments, 

 which spring from all parts of the branches. In others, pro- 

 per receptacles, formed of minute, branching filaments closely 

 whorled roimd a central axis, and compacted together by la- 

 teral cohesion, either terminate the larger divisions of the 

 frond, or are borne on short, lateral ramuli or peduncles. 

 To the filaments composing these capiiula or knob-like 



