THALLOGEN^. 717 



is principally employed for flavouring. It is imported in a dry state from the 

 Continent. 



Exidia Auricula Jitdce, Jew's Ear, is reputed to possess astringent and dis- 

 cutient properties, when applied externally in the form of a decoction, poul- 

 tice, &c. E. hispidula is used in China as a styptic, and as a food mixed in 

 soups, &c. It is known there under the name of Moghi, signifying ears of 

 trees. 



Cordyceps (Sphccri'a).— The disease called Ergot, which occurs in the grains 

 of Rye and other gr;isses, is produced by Cordyceps purpurea. (See Proper- 

 ties and Uses of Funai.) C. Robertsii, sinensis, entomorrhiza, and other 

 species, frequently attack caterpillars in a living state, which they destroy as 

 their mycelium developes. The remains of the caterpillar with the developed 

 fungus of C. sinensis, is a highly esteemed drug in China, where it is much 

 used as a tonic. 



Uredo. — The species of this genus produce the diseases of Corn and other 

 cultivated plants, called blights, rusts. Sec. 



Puccinia graminis is the fungus which produces the Mildew of Wheat. 



Oidium The Vine Fungus is commonly supposed to be a species of this or 



a nearly allied genus. It would appear, however, that the so-called fungus, 

 Oidmm, is a mycelial form composed of conidial cells of some other fungus, 

 probably a specifs of Erysiphe. 



Ptnicilliujji glaucum, Mucor mucedo, Aspergillus glaucus, Botrytis vul- 

 garis, ^c. in their fully developed conditions (figs 1.50—1.52), form thevarious 

 kinds of Moulds already noticed. (See Properties and Uses of Fungi.) Bo- 

 trytis infestans is the fungus seen in the Potato disease. The so-called 

 Vmegar plant, which, by its growth in saccharine liquids at moderate tempe- 

 ratures, converts them into vinegar, appears to be a mycelial st;-te of Penicil- 

 lium glaucum ; and the Yeast plant (jig. 142), which by its vegetation at a 

 high temperature, causes fermentation in bread, beer, &c., would seem like- 

 wise to be a mycelial state composed of conidial cells of a species of Peni- 

 cillium. 



Natural Order 295. Alg^. — The Sea-weed Order. — Paren- 

 chymatous cellular plants ; growing in salt or fresh water, or in 

 moist situations. The thallus is foliaceous and branched (Jig. 

 153), or filamentous (figs. 828 and 836), or pulverulent. Many 

 Algae are microscopic, and others are of large size. In colour 

 they are usually greenish, rose-coloured, or brown. They are 

 reproduced in various ways. (See pp. 388 — 393.) 



Division of the Order, ^c. — The order is commonly divided 

 into three sub-orders, which are frequently regarded as distinct 

 natural orders; these are known under the names of the Mela- 

 nosporece or Fucoidece ; the Hhodosporece or Floridece ; and the 

 Chlorosporece or Confer voidece. To these sub-orders may be 

 added two others, called respectively, Diatomacece, and Voloo- 

 cinece. The distinctive characters of these different sub-orders 

 may be briefly described as follows : — 



Sub-order 1. Melanosporece, Fucoidece, or Brown-coloured Algce. 

 — Multicellular Algae, growing in salt water, forming a 

 foliaceous (fig. 153), or filamentous thallus (fig. 836), and 

 of an olive-green or olive -brown colour. Keproduced by 1. 

 Zoospores (fig. 836); 2. Spores (figs. 153, t, and 837); and 

 3, Antheridia (figs. 838 and 839.) (See pp. 391—393.) 

 Examples : — Sargassum, Halidrys, Fucus, Chorda, Lamina- 

 ria, Ectocarpus. 



Sub-order 2. Rhodosporece, Floridece, or Rose-coloured Algce. — 

 Marine multicellular plants, with a foliaceous or branched 



