84 FUNGI. 



rounded by a varying number of cortical cells of similar size the so-called 

 " siphons." 



Order 13. Ceramiaceae. Pretty Algas, often branched dichotomously, or 

 unilaterally pinnate. Spcrmothamnion, Oriffittisia, Callithamnion, Ceramiuni, 

 Ptilota. 



Sub-Family 4. Cryptonemiales. The cells formed by the coalescence 

 of the auxiliary cells and the ooblastema-filaments, produce the gouimoblasts. 

 The carpogoniiim-jilaments and the auxiliary cells are scattered singly in the- 

 thallus. 



Order 14. Gloiosiphoniaceae. Gloiopeltis. 



Order 15. Grateloupiaceae. Halymenia, Cryptonemia. 



Order 16. Dumontiacese. Dumontia, Dudresnaya. 



Order 17. Nemastomaceae. Furcellaria, which has dichotomously 

 branched, round shoots, is common on the coasts of Great Britain. 



Order 18. Rhizophyllidaceae. Polyides, Rhizophyllis. 



.Order 19. Squamariaceae. The Algas belonging to this order form crust- 

 like coverings on stones, mussel-shells, and on other Alga?, but are not them- 

 selves incrustated : Petrocelis, Cruoria, Peyssonellia. 



Order 20. Corallinaceae. Partly crustaceous, partly erect, branched Algae, 

 thickly iucrusted with lime, so that a few species (Lithothamnia, also called 

 Nullipora) occur in fossilized condition from Jurassic to Tertiary periods. 

 Melobesia, Lithophyllum, Lithothamnion, Corallina. 



USES. " Carragen " is the thallus of Ghondrus cricpus (Irish 

 Moss) and Gigartina mamillosa. It is a common article of food on 

 the coasts of Ireland, and swells to a jelly when cooked. It is 

 officinal. Rhodymenia palmata is generally eaten as food in 

 Ireland and in some places on the west coast of Norway ; it is 

 also used as food for sheep and hence is termed " Sheep-seaweed." 

 Agar-Agar is the jelly obtained from species of Gelidium and 

 Gigartina growing in China and Japan. 



Sub-Division III. FUNGI. 



Mode of Life. The Fungi have no chlorophyll, and are thus 

 unable in any stage of their existence to assimilate carbon ; they 

 must therefore live as saprophytes or parasites. There is, however,, 

 no strong line of demarcation between these ; many Fungi com- 

 mence as true parasites, but only attain their full develop- 

 ment upon or in dead plants or animals (Rhytisma, Empusa). 

 Many saprophytes may occasionally appear as parasites, and are 

 then designated "facultative parasites" (Nectria' cinnabarina* 

 Lophodermium pinastri), in contradistinction to those which only 



