26 LAMINARIACE.E. 



1. C. Cabrera, Clem. ; frond irregularly dichotomous, linear, 

 narrow, flat, midribbed ; branches here and there constricted. 

 Harv. Phyc. Brit. t. xiv. Sporochnus Cabrera, Ag. ; Harv. 

 in Mack. Fl. Hib. part 3, p. 154; Turn. Hist. t. 140. 



Thrown up from deep water, very rare. Perennial ? Winter. Youghal, 

 County Cork, Miss Ball. Plymouth Sound, Rev. W. S. Hore and Dr. 

 Cocks. Root a shapeless woolly tuber. Stems 6 8 inches high, much 

 branched in an irregularly dichotomous manner, flat, nerveless, except 

 near the base, where there is an obscure midrib, coriaceo-cartilaginous. 

 Branches erect, with acute axils, distichous, alternate, narrow below, be- 

 coming rather broader upwards, here and there constricted, the apices 

 truncate and often discoloured. 



ORDER III. LAMINARIACE^. 



Laminarieae, Grev. Ala. Brit. p. 24. J. Ag. Symb. p. 4. 

 Sp. Ala. p. 121. Endl. 3d Suppl. p. 26. Kliiz. Phyc. Gen. 

 p. 344, and part of Chordese, p. 333. Laminaridae, Lindl. 

 Veg. King. p. 22. 



DIAGNOSIS. Olive-coloured, inarticulate sea-weeds, whose 

 spores are superficial, either forming indefinite cloud-like 

 patches or covering the whole surface of the frond. 



NATURAL CHARACTER. Root rarely a simple disk, com- 

 monly a conical mass composed of numerous stout branching 

 fibres compacted together. Fronds of an olive-brown or 

 olive-green colour, becoming darker on exposure to the air ; 

 sometimes tough and leathery, sometimes delicately membra- 

 naceous, fibroso-cellular ; frequently of very large size, either 

 simple and tubular, or furnished with a more or less distinct 

 stipes or stem, terminating in a leafy frond. In the simplest 

 kinds the frond is a hollow, membranous bag, contracted at 

 the base into a little stalk, and gradually tapering to the apex ; 

 in others a little more perfect, the frond is tubular, the tube 

 divided into several compartments by transverse partitions 

 placed at equal distances across its cavity. In more perfect 

 genera the frond is distinctly divisible into two portions ; a 

 cylindrical or compressed stem, and a flattened leafy blade. 

 The stem is either simple or branched, and is usually solid, at 

 least in its lower part, and in all cases bears the leafy expan- 

 sion at its summit, or at the summits of its branches. This 



