SECTION 17.] 



THALLOPHYTES. 



173 



cells lengthen and branch, growing by the absorption through their whole 

 surface ot" the decaying, or orgunizable, or living matter wiiieh they feed 

 upon. In a Mushroom (Agaricus), a kuol)by mass is at length formed, 

 which develops into a stout stalk (Sl/'pr), bearing tlie cap {PUeus) : tlie 

 under side of tlic cap is covered by the Ih/nienium, in this genus consisting 

 of radiating plates, tlie gills or LamelLe ; and these bear the powdery spores 

 in immense numbers. Under the microscope, the gills are found to be 

 studded with projecting cells, each of which, at the top, produces four 

 stalked spores. These form the powder wliicii collects on a sheet of paper 

 upon which a mature Mushroom is allowed to rest for a day or two. (I'ig. 

 581-586.) 



517. The esculent Morel, also Splia;ria (Fig. 585, 586), and many other 

 Fungi bear their spores in sacs (usci) exactly in the manner of Lichens 

 (515). 



518. Of the Moulds, one of the commoner is the Bread-Mould (Fig. 

 587). In fruiting it sends up a slender stalk, which bears a globular sac ; 



Fig 581 Agaricus campestris, the common edible Mushroom. 582. Section 

 of cap and stalk. 583. Minute portion of a section of a gill, shbwmg some spore- 

 hearing cells, much magnified. 584. One of these, with its four spores, more 



magnified. . , , , i 



Fig. 585. Sphjeria rosella. 586. Two of the asci and contamed double spores, 

 quite like those of a Lichen ; raucli magnified. 



