NATUKAL ORDERS, 



507 



of filamentous threads, appearing like the roots of the fungus 

 that arises from them, and to a certain extent performing the 

 functions of roots. In the Agarics or Mushroom.s there ap- 

 pears first a roundish protuberance on the mycelium, vrhich en- 

 larges rapidly, bursts an outer covering {volva)^ and protrudes 

 a thick stalk {stipe\ bearing on its summit a rounded portion, 

 which soon expands into ihopileus or cccp. On its under sur- 

 face are situated the Imnellce or gills {hy7nenium\ consisting of 

 parallel plates which bear naked sporules over their whole sur 

 fiice. 



a. Properties : tonic when dry, narcotic ■when juicy ; some are edible, others 

 poisonous, , 



Genera. — Lycoperdon, Mucor, Uredo, Agarlcus, Boletus. 



569. CHAEACEiE, the Cliara Tribe. — Aquatic plants composed 

 of tubular cells, often with a set of smaller tubes inclosing a 

 large central one. Leaves or branches consisting of verticillate 

 tubes. Organs of reproduction of two kinds — a round, red 

 globule, and an axillary nucule which contains the germinating 

 body. 



Genus.— Chara. 



570. Algje, Seaweeds.— CoWvlSiV plants, found both in fresh 

 and salt water. Some have the distinction of stems and fronds ; 

 others show simple or branching, solid stems 

 only ; and others are mere leafy expansions, of 

 various colors, green, olive, or rose-red. From 

 these we descend to the green Confervse of 

 pools and ditches, which grow by a subdivision 

 or lateral extension of cells ; and lastly, as the 

 lowest form of vegetation, the plant is reduced 

 to a single cell, producing new individuals by 

 the division of the primary cell. Eeproductive 

 organs consist of spores contained in pe'risjpores 

 or sjporecases. These are sometimes congre- 

 gated to2;ether in receptacles of difierent kinds. 

 (Plate YIII., Figs. 8, 9, 10, 11.) 



Genera. — Fucus, Halymenia, Ulva, Conferva, N"ostoc. 



Fig. 221, a, Protococcus virldis ; b, the same beginning to 

 develop ; c, the same more advanced ; d, e, ScmzoaoNroM jmi- 

 rale. 



13* 



