284 Ethel McLennan : 



The following figures are extracted from his paper : — 

 I. — Without nitrogen mounre. 



Nitrogen 



Dry Weight .— 



tfr. absolute nig. per cent.- 



Lolium temiilentum - - 5.173 - 30.35 - 0.59 

 Lolium italiciun - - 0.974 - 6.69 - 0.69 



Eoot mixture - - 3.619 - 7.78 - 0.22 



'i'otal - -. 9.766^rr. - 44.S2nig - 0.46% 

 II. — Manured with 50 mg. of nitrogen. 



Nitrogen 



The nitrogen content of Lolixtm temulentum plants, when fer- 

 tilised with potassium nitrate, is seen by the above figures to in- 

 crease markedly as compared with that obtained for unfertilised' 

 plants, i.e., plants watered with tap water only. Not only is this; 

 so, but the increase is nearly as great as that obtained for Lolium 

 italicum. The small difference between the percentage results for 

 both species is not outside the limit of experimental error, especi- 

 ally when the sources of such error are as gi-eat as in tlie experi- 

 ment in question. 



Kayner (20) wlien dealing with the symbiotic relatiun of an asso- 

 ciated fungus in Calluna I'ldgari-^t, refers to the case of Darnel 

 grass, and says: " Some degree of symbiosis has been inferred, but 

 the experiments of Hiltner to establish nitrogen fixation for this 

 fungus are inconclusive." 



In describing the distril)ution of the fungus (a peculiar mycor- 

 rhizal form) found in Calluna vulgaris,. Rayner draws attention tO' 

 the fact that in many points it resembles the fungus in Darnel. 

 The fungus from Calluna was isolated and grown in pure culture, 

 and was found to be closely related to the genu? I'hnma: nitrogen- 

 fixation was suggested as its function. Duggar and Davis (21) 

 showed that Phoma Beiae, when grown on mangel or sugar beet 

 decoction, produced a nitrogen gain of from 3.022 — 7.752 mg., 

 pointing definitely to nitrogen fixation for this particular fungal' 

 species. In fact, it Avas the only definite positive result obtained' 

 from all the forms experimented with. 



