Minnesota Plant Life. 77 



celain kettle. The lining-layer is made up entirely of sacs and 

 accessory threads running parallel with them. All of the sacs 

 are cylindrical, slender and arranged perpendicular to the inner 

 surface of the cup, while in each sac there are eight spores, ovoid 

 in shape and developed in a row just as in the morel. 



Another kind of cup-fungus is scarlet, almost as large as the 

 one just described and equally familiar to most persons who go 

 into the woods with open eyes. Besides such large cup-fungi 

 there are a great number of smaller kinds, some of them grad- 

 ing down to the size of a pin-point, while between these and the 

 large ones are all sorts of intermediate sizes. They differ too 

 in color and in form and many of them are saucer-shaped, or 

 merely flat discs, circular in outline. Such small discs of a 

 bright yellow, or bright red color, are abundantly produced 

 upon decaying wood and leaves. 



In distinguishing the different kinds of cup-fungi the char- 

 acter of the margin should be observed. This is sometimes 

 furnished with bristles or scales ; sometimes it is smooth ; some- 

 times it is rolled back, or it may be rolled in over the centre of 

 the cup, disc or saucer. It is not possible, however, to recog- 

 nize exactly all the different cup-fungi without an examination 

 of their spores, for special sorts develop special kinds of spores 

 in their sacs. Sometimes the spores are without partitions, 

 while in other instances they are divided into little chambers. 

 They may be smooth or provided with knobs, spines or emer- 

 gences. Growing in the same layer with the sacs are com- 

 monly to be found much slenderer threads, which help to keep 

 the sacs moist while they are developing their rows of spores. 

 When the cup-fungus has matured its spores, the ends of the 

 sacs which all lie at the same level in the surface of the cup- 

 lining open or dissolve, and the spores are then thrown out. 



One kind of cup-fungus which is common on manure-piles 

 has a special explosive method of ejecting its spores. If such a 

 cup is taken between the finger and thumb, held to the light and 

 pressed gently, the sacs all open at once and violently eject their 

 spores, so that for an instant a little wreath of smoke seems to 

 fly from the top of the cup. This phenomenon is caused by a 

 cloud of several thousand spores escaping simultaneously. The 

 spores in certain species are net individually shot out from the 



