Plate III. 



Fig. 9. PYCNOPIIYCUS TUBERCULATUS. 



Colour. Wlioii growing, a fine olive; when dry, black. 

 Substance. Tough, leathery. Brittle when dry. 



Character of Frond. Cylindrical; about as thick as a goosequill; branched. 

 Branching, repeatedly forked {dicJiotomous) . Root fibrous. 



Measurement. From 12 to 20 inches long. 



Air-vessels. Inflations in the branches; but often wanting. 



Fructification. Minute seeds [spores) in special receptacles at the ends of the 

 branches, thickening them. Receptacles long; obtuse at the tips ; 

 tubercled; yellowish. 



Habitat. Cornwall and Devonshire. West of Ireland. Jersey. In rock- 

 pools near low-water mark. 



By a change of classification and name, this plant is now Fucodium tuhercii- 

 latum. The Family Faoodlum comprehending also those members of the old 

 Family Fucus, which arc destitute of a midrib ; viz. F. nodosus, F. Maclcaii, and 

 F. canaliculatas. 



Fig. 10. FUCUS VESICULOSUS, 



Colour. When fresh, olive-brown; when dry, black. 

 Substance. Tough, leathery; slimy feeling. 



Character of Frond. Flat, midribbed, branched, occasionally twisted; branch- 

 ing, forked [dlchotomous) ; margins smooth [entire). 



Measurement. Sometimes extending to several feet in length. Dwarf 

 varieties from 1 to 2 inches. 



Air-vessels. Inflations in the branches; round; largish; mostly in pairs; often 

 one on each side the midrib. But air-vessels are not unfrequently 

 wanting. 



Fructification. Minute seeds [spores) in special receptacles at the ends of the 

 branches. Receptacles more or less oval; large; orange-coloured; slimy; 

 tubercled. 



Habitat. All round our coasts; abundant. On all rocks, stones, piers, quaj^s, 

 &c. which become exposed at low water. Up rivers too, in similar 

 situations, as long as the water is brackish; but under such circum- 

 stances dwarfed and destitute of air-vessels. 



A most widely distributed species. Found on the ISTorth Atlantic coasts, and 

 extends even to the Tropics, Arctic Ocean, and Pacific coasts of N. America, 

 Kamschatka, &c. 



6 



