THE INFLUENCE OF ^lUSHROO^IS ON THE GROWTH OF 



SOME PLANTS* 



By Geo. F. Atkinson 



The problem. — The large number of mushrooms, or fleshy fungi, in- 

 cludmg the large basidiomycetes which are developed annually and then 

 disintegrate, represent a large amount of plant substance. Some of the 

 food substances of certain fleshy fungi are probably in a form which is 

 available for the green plants as food, but the large number of the basidio- 

 mycetes make use of organic matter for food which is not in a condition 

 to be used by the green plants. The problem set for this investigation is 

 to determine if the substance of these fungi whether derived from food 

 substances already available for the green plants or from organic matter 

 not available to them can be used as food to any extent by the green 

 plants in an undecomposed condition, or when partially decomposed by 

 bacteria or fungi, or both, or when the substance is completely decomposed. 

 It would also include a study of the influence of decoctions of mush- 

 rooms, or of decaying mushrooms in dift'erent stages of putrefaction on 

 the growth of green plants. Finally it should include the determination 

 of the products of decomposition of these fungi to learn the final end 

 products of decay, and their relation to the nutrition of green plants, 

 or to the questions of increase or decrease of available substances for 

 the nutrition of green plants. All these fungi are of importance in the 

 matter of the disintegration of plant remains, reducing the bulky and 

 firm parts of dead plants to a finer condition of forest or vegetable mold 

 which in itself is beneficial since this detritus improves the physical con- 

 dition of soils, and represents steps also in returning at least some of the 

 organic matter not absorbed as food by these plants to a condition in 

 which it can again enter the circulation of food substances for autotrophic 

 green plants. In addition to this is the actual substance of the fleshy fungi 

 lost, or is all or a part of it finally returned to the circulation again? 



Some preliminary experiments were conducted during the spring of 

 1905 with Agaricus campestris as the source of plant food for corn, peas, 

 beans and buckwheat. Sterile sand was employed as a substratum, some 

 pots being of pure sand for checks, while in others fresh mushrooms were 

 crushed and plentifully mixed with the lower layer of the sand. Where 

 there was an abundance of the mushroom substance and near the surface 

 the decomposition products formed in the decay of the mushroom either 

 caused the seed to rot, or prevented the growth of the roots. In other 

 cases where the mushroom substance was less in quantity and in the 



♦Contribution from the Department of Botany of Cornell University No. 112. 



303 



