102 ACOTYLEDONS. ALGJE. tSphcCTOCOCCUS. 



* Frond plane or compressed. 



1. S. dentatus, frond flat membranaceous branched alternately 

 pinnatifid, ramuli alternate linear sharply toothed at the apices, 

 capsules pedunculate axillary lanceolate and urceolate. Turn. 

 Ag. p. 22. Fttciis dentatus," Lighlf. p. 952. Turn. Hist. Fuc. 

 //13. E.B.t. 1241. 



HAB. Firth of Forth, lona, and other shores, plentifully. 

 From 5 inches to a foot long, dark reddish brown, opaque. 



2. S. rubens, frond membranaceous obsoletely ribbed proliferous 

 from the surface, branches elliptical simple and forked, round- 

 ish peltate leaves and hemispherical externally uneven tubercles 

 sessile on the disk. Turn. Ag. p. 23. Fucus rulens, Turn. 

 Hist. Fuc. t. 42. E. B. t. 1053. Fucus prolifer, Lightf. 

 p. 949. t. 30. 



HAB. Shores of the western coast, adhering to shells and stones, 

 Lightf. Rare and only among rejectamenta in the Firth of Forth, 

 Mr. Greville. 



3 7 inches long, fine reddish rose colour, approaching to purplish. 



3. S. crispus, frond cartilaginous flat nerveless dichotomous, en- 

 tire at the margins curled segments subcuneiform the upper- 

 most narrowest, tubercles roundish solitary scattered jmmersed 

 in the substance of the frond concave on one side deciduous. 

 Turn. Ag. p. 24. Fucus crispus, Turn. Hist. Fuc. t. 210 and 

 217. Fucus ceranoides, Light}', p. 913. 



y. siellaius, frond submembranaceous, branches dilated upwards 



divided at their apices into very numerous clustered shortish 



laciniae. Turn. 

 b\ cequalis, frond cartilaginous thick, all the branches equal and 



linear, the extreme segments obtuse. Turn. F. crispus, E. B. 



t. 22S5. 

 HAB. Rocky shores, a. and y. plentiful. . Firth of Forth, Mr. Greville. 



A most variable species both in form and in colour. From 3 to 6 



inches high, usually of a purplish or reddish cast, often inclining to 



green, especially in decay. 



4. S. mammillosus, frond cartilaginous channelled on one side 

 nerveless dichotomous elongato-cuneiform proliferous from the 

 sides and surface entire at the margins, tubercles spherical all 

 over the frond on very short peduncles. Turn. Ag. p. 25. 

 Fucus mammillosits, Turn. Hist. Fuc. t. 218. .E. B. t. 1054. 

 Fucus ceranoides e., Lightf. p. 916. 



/3. linear is > frond narrow linear, apices bluntish and emarginate. 

 Turn. Fucus ceranoides ., Lighlf. p. 917- 



HAB. Rocky shores, frequent. . On the Cramond Island, Lightf. 



3 6 inches long, very variable in width upwards. Colour purplish red. 



S.S.membranifolius, stipes cylindrical branched, apices expanded 

 into a subcuneiform leaf between membranaceous and cartila- 

 ginous fiat nerveless bilobed or dichotomous, tubercles oblong 



