DEVELOPMENT OF I III-. WlSlllt-OOW. 



9 



tion shows, of myccliLim threads. The center of tlie gill is called 

 the tnimj. The trama in the case of this plant is made up of threads 

 with ratlier long cells. Toward the outside of the trama the cells 

 branch into short cells, which make a thin layer. This forms the 

 subliymciiium. The subhymenium in turn gives rise to long club- 

 shaped cells which 

 stand parallel to each 

 other at right angles 

 to the surface of the 

 gill. The entire slu- 

 face of the gill is 

 covered with these 

 c 1 u b- sha ped cells 

 called basidia (sing. 

 hasifiuni). Each of 

 these c 1 u b - s h a p e d 

 cells bears either two 

 or four spinous pro- 

 cesses called sh't'igniata 

 (sing. stcrignuT), and 

 these in turn each bear 

 a spore. All these 

 points are well show n 

 in Fig. 8. The basidia 

 together make up the 

 hymciiiu))!. 



Wood Destroying 

 Fungi. — Many of the 

 mushrooms, and their 

 kind, grow on wood. 

 A visit to the damp 

 forest during the sum- 

 mer months, or during 



the autumn, will re\eal large numbers of these plants growing 

 on logs, stumps, from buried roots or rotten wood, on standing 

 dead trunks, or even on living trees. In the latter case the 

 mushroom usually grows from some knothole or wound in the 

 tree (Fig. 9). Man\- of the forms which appear on the trunks of 

 dead or living trees are plants of tough or woody consistency. They 

 are known as shelving or bracket fungi, or popularly as "fungoids " 

 or " fungos." Both these latter words are \ery unfortunate and 

 inappropriate. Many of these shelving or bracket fungi are perennial 





■»v 



11 



Fk.ikk I.). — I'()ly])onis horealis, showinji wtmnd at base of 

 hemlock >iiruce caused by falling tree. Bracket fruit 

 foini of Polyporus borealis growing from wound. (I'S 

 natural size.) 



