1902.] Seed-fungus o/Lolium temulentum, L., the Darnel. 29 



Summary. 



1. The proportion of grains without to those Avith the fungus layer 

 outside of the aleurone of L. temulentum varies, but is usually from 

 80 — 100 per cent. In some cases the microscopic differences are 

 sufficient for diagnostic purposes. 



2. The hyphae sometimes penetrate the aleurone at any point and 

 invade the starch-endosperm, but no fructification or spores of any 

 kind have been seen. 



3. There exists in the nucellus, at the base of the scutellum and at 

 the lower end of the inner groove of the grain, a layer of hyphae which 

 lies directly against the embryo, constituting an infection layer. 



4. Embryos of the grain of L. temulentum in a proportion approxi- 

 mately equal to that of the occurrence of the fungus in the grains, 

 always contain hyphae in the growing point, and these hyphae can be 

 traced to their origin in the infection layer. They remain in the grow- 

 ing point throughout the life of the plant. 



5. The course of the hyphae is always intercellular. 



6. There is no reason for the supposition of any so-called " my co- 

 plasm " in the embryo : the fungus always exists as distinct hyphae. 



7. In the growing plant the fungus forms networks in the leaf-bases, 

 of which the function has not yet been determined. 



8. The nucellar hyphae of the grain undergo degeneration dining 

 germination without the formation of spores. 



9. All attempts to obtain cultures of the nucellar hyphae have 

 failed, indicating either that the hyphae here have lost their vitality or 

 else, as is more probable, that they are too closely adapted to a parasitic 

 (or symbiotic) life to allow of artificial culture. 



10. In the young ovary a tongue of hyphae reaching from the funicle 

 to the micropyle on the inner side of the grain, becomes detached 

 from the remaining nucellar hyphae by the elongation of the ovule and 

 the cessation of hypbal growth in the funicle. 



11. Infection takes place from this layer as soon as the growing 

 point of the embryo has appeared as a recognisable rudiment. 



12. The fungus of other species seems very probably identical 

 with that of L. temulentum, as cross-infections seem to be possible by 

 grafting. L. multifl.orum, Lam., and L. italicum, Braun., also contain a 

 hyphal layer. 



13. There are serious objections to the reference of this fungus to 

 the Ustilagineae, to the ergot-forming Pyrenomycetes or the Hypho- 

 mycetes (such as Woronin and Prillieux and Delacroix have described 

 for poisonous rye), or to the suggestion that it is a Uredine. 



14. The effect of the fungus upon its host seems rather beneficial 

 than detrimental, and several facts point toward the confirmation of 



