102 ACOTYLEDONS. ALG.li:. SpIlCOroCOCCUS. 



* Frond plane or covipressed. 



1. S. dentatus, frond flat membranaceous branched alternately 

 pinnatifid, ramuli alternate linear sharply toothed at the apices, 

 capsules pedunculate axillary lanceolate and urceolate. Turn. 

 A3;, p. 22. Fucus dentatus, L'lghlf. p. 952. Turn. Hist. Fuc. 

 ^^13. E.BJ. 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 hemisphasrical externally uneven tubercles 

 sessile on the disk. Turn. As;, p. 23. Fucus nibens. Turn. 

 Hist. Fuc. t. 42. E. B. I. 1053. F'ucus prolifer, Lighff. 

 p. 949. /. 30. 



Hab. Shores of the western coast, adliering to shells and stones, 

 Lighff. 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 immersed 

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

 Tur7i. y}g. p. 24. Fucus cr'ispus, Turn. Hist. Fuc. t. 216 and 

 217. Fucus cerarioides, Lighff. p. 913. 



y. stel,lat?i^, frond subniembranaccous, branches dilated upwards 



divided at their apices into very numerous clustered shortish 



lacinia;. Tiirn. 

 8. cecjua/is, frond cartilaginous thick, all the brandies equal and 



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



t. 2285. 

 Hab. Rocky shores, a. and 7. 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 piu-plish or reddish cast, often inclining to 



green, especially in decay. 



4. S. mammillosus , frond cartilaginous channelled on (me side 

 nerveless dichotomous elongato-cuneiform proliferous from the 

 sides and surface entire at the margins, tubercles sphaerical all 

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

 Fucus mammillosus, Turn, Hist. Fuc. t. 2 IS. E. B. t. 1054. 

 Fucus ceranoides s., Lrghtf.p. 916. 



^. linearis, frond narrow linear, apices bluntish and emarginatc. 

 Turn. Fucus ceranoides ^., Lighff. p. 917- 



Hab. Rocky shores, frequent, l,. On the Cramond Island, Lighff. 



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



5,S. memhranifolius, stipes cylindrical branched, apices expanded 

 into a Siubcuneiform leaf between membranaceous and cartila- 

 ginous flal iicrvclcj.s bilobed or dichotomous, tubercles oblong 



