SPOROCHNACE^. 49 



This is a very delicate and beautiful species, and is 

 widely distributed in the higher latitudes, both north 

 and south. Unlike most other plants, it appears to in- 

 crease in luxuriance as it penetrates into the regions of 

 the greatest cold. 



Genus VIII. ARTHROCLADIA. 



Frond thread-like, cellular, knotted, covered with whorls 

 of jointed, bipinnate filaments, and traversed by a tube which 

 is divided transversely into air-cells, fructification in bead- 

 like, still ked receptacles on the filaments. — Abthbocladia, 

 from the Greek arthron, a joint, and Mados, a branch. 



This genus contains only one species, 



Arthrocladia villosa. Shaggy Arthrocladia, 



which is an annual, and grows in deep water. It is 

 sparingly distributed on the shores of Europe, and has 

 been found in North America. It is most frequent on 

 the south coast of England and in Jersey. I well re- 

 member the delight of finding fine specimens of this 

 plant and of the allied species, Sporochnus pedunculatus 

 and Desmarestia viridis, all together, and for the first 

 time, in Greve d'Azette, at the back of Elizabeth Castle, 

 St. Helier, and I trust that some at least of my readers 

 may be equally fortunate. 



Genus IX. SPOROCHNUS. 



Erond thread-like, solid, composed of two kinds of cells, 

 those at the axis and circumference very small, those inter- 

 vening much larger. Fructification stalked, oblong recep- 

 tacles, crested with tufts of slender, jointed fibres, and com- 

 posed of branched spore-bearing filaments arranged round a 

 slender axis. — Spoeochn0s, from the Greek sporos, a seed, 



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