296 GENERAL MORPHOLOGY OF PLANTS 



prominent sack or bag around the base of the stem. Amanita 

 verna is considered by some as a white form of this species. 

 This is common in America. Amanita map pa has a pale yellow 

 cap; the volva splits transversely, leaving portions on the cap in 

 the form of floccose patches or warts. The lower part is left as 

 a narrow rim on the outer edge of the broad bulb of the stem. 

 The poisonous principle in the above three species is phallin, a 

 substance thought to be of an albuminous nature. It dissolves 

 the blood corpuscles and the serum escapes into the alimentary 

 canal. No antidote is known. Another poisonous species is 

 Amanita muscaria (fig. 266), the " fly agaric." It has a red, or 

 yellowish red cap, white gills and stem. The volva splits trans- 

 versely, the upper part being left as coarse white warts on the 

 pileus which is striate on the margin. The lower part of the volva 

 is left near the base of the stem, as one to three coarse rings on the 

 bulb. The poisonous principle in the fly agaric is muscarine. It 

 paralyzes the nerves which control the action of the heart, and if 

 not counteracted results in death. Hypodermic injections of small 

 doses of atropin stimulate the heart to greater activity, thus 

 counteracting the poison until its effect has disappeared. 



Bracket Fungi or Pore Fungi. 



463. The bracket fungi. These are the firm fungus growths 

 of a shelving form so common on dead or living trees, stumps, 

 logs, etc., in the forest. The under surface is very finely honey- 

 combed with minute tubes or pores (characteristic of the family 

 Polyporacece). The fruiting surface or hymenium lines all these 

 pores. Some of these bracket fungi are hoof-shaped, or tongue- 

 shaped. They grow singly or in clusters. In some of them the 

 age can be determined by counting the number of concentric 

 rings on top, as in the pine-inhabiting polyporus which grows on 

 the conifers, the charred polyporus growing on birch, beech, maple, 

 oak, apple, etc. One of these has been found which was eighty 

 years old. This one, and related bracket fungi, were used in 

 early times as " tinder " for holding and lighting fire. Some are 



