326 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 mappa 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. 

 One 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. The heat of cooking destroys phallin, but does not de- 

 stroy another deadly poison, Amanita-toxine. For this poison 

 no antidote is known. Another poisonous species is Amanita 

 muscaria (fig. 280), the "fly agaric." It has a red, or yellowish 

 red cap, white .gills and stem. The volva splits transversely, 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 of 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. 



478. 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 

 Polyporacetz). 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 



