Minnesota Plant Life. 69 



as a turkey's egg. Both this and its smaller relative of the pas- 

 tures open somewhat irregularly at the end away from the 

 ground, or perhaps at the side. Among the short-stemmed 

 puff-balls two or three large varieties are found ; one, the giant 

 puff-ball, occurs larger than a man's head and almost spherical 

 in shape, while another is in outline somewhat like a dinner bell 

 with the mouth closed and mound-like. 



Earth-stars. An interesting variety of puff-ball is the earth- 

 star. This has an outer skin that splits radially, as one peels 

 an orange, revealing the inner skin that encloses the spores. 

 The little mouths of the earth-stars are nicely protected by a 

 group of bristles which, by their sensitiveness to moisture, as- 

 sist the distribution of the spores under conditions which are 

 favorable for their germination. 

 Apparently the use to the plant of 

 splitting back the outer skin is the 

 additional height that it attains 

 from which its spores can be dis- 

 tributed. The points of the sec- 

 tions which have split bend under 

 and lift the central ball a half inch 

 or more into the air, and the spores 

 have an added opportunity of catch- 

 ing some wind current, which, if 

 they were closer to the ground, FlG - 24 - Tufted P uff - ba11 - After 



Uoyd. 



might not distribute them so far. 



Slitted puff-balls. A rather large puff-ball with a short stalk 

 and a white egg-shaped head is sometimes found in fields and 

 door yards, the small end of the egg pointing upward and the 

 large end hanging down over the stalk which seems to grow up 

 into a depression there. These puff-balls open by slits close 

 down to the stalk, and the interior is found to be occupied by 

 irregular, broken, brown plates, radiating vaguely from the 

 stalk-region somewhat like the gills of the mushroom. 



BircTs-nest-fungi. Among all the puff-balls few are more in- 

 teresting objects than the little bird's-nest-fungi. There are 

 three sorts of these common in Minnesota. None of them is 

 very large for they do not exceed a quarter to a half inch in 

 diameter. They are often seen growing on the planks of old 



