210 



ALG^ 



is eaten in Scotland under the name of ' dulse.' Chondrus crispus (L.) 

 is known, when dried, as ' carrageen ' or ' Irish moss.' Gracilaria lichen- 

 oides (L.), which yields copious gelatine, known as ' Fucus amylaceus,' 

 is largely used as an article of food in Ceylon and on other tropical 

 coasts. Japanese isinglass is a product of species of Gelidium. The 



O '^ C> drOO 



O a ^ c^o^ 







Fig. 187.— Vertical median section of swelling on frond of Gracilaria cott/erz'oides Grev. 

 /, /, cells of procarp , ^c, placental cells ; s, s, s, spores ( x 400). (After Johnson.) 



substance known to microscopists as 'agar-agar' is yielded also by 

 Gracilaria lichenoides, Eucheuma spinosa (Ag.), and other seaweeds. 

 Several other species are employed in different parts of th(=t world as glues 

 and varnishes. ^Marchesettia spongioides (Hauck) (Areschougiacese), 

 from Singapore, has a remarkable resemblance to a sponge. 



Literature. 



Berthold — (Cryptonemiacege) Fauna u. Flora Golfes Xeapel, 1884. 

 Johnson — (Gracilaria) Annals of Botany, i. 1888, p. 213. 



The Squamariace^ (Hildenbrandtia, Nard., Cruoria, Fries, Peysson- 

 nelia. Dene., Szc.) are a small group of small marine, or rarely fresh-water 

 Alga5, growing on stones or on the shells of molluscs or Crustacea, or 

 attached to larger algse. The ' frond ' is expanded flat or hemispheri- 

 cal, gelatinous, membranaceous, or crustaceous, with lichen-like habit, 

 composed of a single layer of cells, or more often of short densely 



