f 



64 



MISSOURI BOTANICAL GARDEN. 



pare the way for the blue green alga. Lenticels also occur 

 on the tubercles, which may serve in aerating the root system. 

 Life believed that the tubercles may aid in free nitrogen as- 

 similation for the plant. 



Because of the evidence that the fungus living in the tuber- 

 cles of Podocarpus, A Inus and Elaeagnus, aids in the fixation 

 of free nitrogen for the use of these plants, Hiltner (17) was 

 led to investigate Lolium temulentum, with which, according 

 to Vogel and Nestler, there is associated a fungus that in- 

 habits all the tissues of the plant even including the seed. 

 Lolium italicum, on the other hand, contains no fungus. 

 Plants of both species w T ere grown to maturity in nitrogen- 

 containing and nitrogen-free soil with respective controls. 

 Chemical analysis showed that Lolium temulentum grown 

 in nitrogen-free sand contained far more nitrogen than w T as 

 originally present in the seed, and the plants nourished with 

 nitrogen compounds contained nitrogen far in excess of that 

 which w T as supplied by the solution ; hence Hiltner claimed 

 that the free nitrogen of the air is used by this fungus- 

 containing plant. Luxuriant growth of other plants likewise 

 attacked by fungi was considered as evidence in favor of 

 this view, but it has been shown by Brefeld (4) that such is 

 not the case with the Ustilagineae and it remains to be proven 

 for other fungi. 



Probably one of the most thorough investigations made on 

 an endotrophic mycorrhiza in relation to its host cell is that 

 of Magnus (22), who sets forth very fully the facts found in 

 the rhizome and root of Neottia Nidus avis, where a fungus 

 enters from without and fills a definite concentric layer of 

 cells. All the infected cells do not react alike, for in certain 

 ones the fungus destroys the protoplasm and forms organs 

 for the purpose of maintaining itself during the w r inter and 

 for the infection of new cells in spring, while in other cells 

 the fungus, after having attained a certain development, is 

 digested for the nourishment of the host, and the undigest- 

 able portion remains and collects in a mass in the center or 

 near the cell wall where layers of cellulose are formed around 

 it. The nuclei of host and digestive cells furnish various phe- 

 nomena which are elaborately described. 



