288 



Fliorow' tested the effect of starvatioi* c.i respiration in Mucor and PsaUiota 

 campestris. In Mucor, respiration immediately falls to a great extent be- 

 cause in this fungus there exists no storage of reserve stuffs in the mycel- 

 lium. In the fruiting body of the basidiomycete, however, there is a great 

 deal of reserve material and, for this reason, it is very independent of the 

 nutritive substratum so that its respiration only falls very slowly with star- 

 vation. In regard to the exchange of the proteins, Fliorow concludes from 

 experiments with Amanita muscaria that the percentage of nitrogen as a 

 whole increases during starvation chiefly because the substances free from 

 nutritive substratum so that its respiration only falls very slowly with star- 

 takes place, which is simultaneous with the periods of spore formation and 

 ripening. A rapid decomposition of the protein follows at once. 



To be sure, the production of carbon dioxid and the taking up of oxy- 

 gen gradually decrease in the starvation of fungi, but in unequal propor- 

 tions, as was observed by Purjewicz-, with Aspergillus niger. 



PrantP has given very good experimental observations on the prothallia 

 of ferns. His experience shows especially that, in the seeding of fern 

 spores, the most diverse variations occur in the prothallia. Some of them 

 have a tissue capable of developing further (meristem), while others lack 

 it and therefore are "ameristic." Earlier investigations* had shown Prantl 

 that the ameristic condition can occur with too small supply of air as with 

 a scanty supply of water and indeed also of mineral substances"'. The ob- 

 servation, that under the most favorable conditions of illumination, ameristic 

 individuals appear when the prothallia grow too close, led to the experiment 

 of testing directly the influence of the nitrogen supply. Spores of the rapidly 

 germinating Osmunda regalis and of Ceratopteris thalictroides were sown on 

 different nutrient solutions. It was thus shown that the spores, germinated 

 in distilled water, produced ameristic prothaUia. They formed surfaces of 

 15 to 25 cells of pretty uniform size and similar content. The chlorophyll 

 grains were poor in starch. On the other hand, the prothallia grown in a 

 nutrient solution, free from nitrogen, but otherwise normal, were dis- 

 tinguished by an extremely large starch content, but otherwise resembled the 

 individuals grown in distilled water. Only the specimens grown in a nutri- 

 ent solution with a nitrogen admixture (0.64 per cent, ammonium nitrate) 

 were meristic. If specimens of meristic prothallia were transferred into a 

 nutrient solution free from nitrogen, the meristem disappeared after 14 days, 

 while the cells as a whole increased, had divided here and there and had been 

 filled with starch. If, on the other hand, ameristic prothallia were placed in 



1 Fliorow, A., Der Einflufs der Ernahrung auf die Atmung der Pilze. Bot. Cen- 

 tralbl. 1901. Vol. 87, p. 274. 



2 Purjewicz, K., Pliysiolog-. Unteisucli. iiber die Atmung- der Pflanzen. cit. Bie- 

 derm. Centralbl. 1902, p. 180. 



3 Prantl, Beobaclitungen iiber die Ernahrung der Farnprothallien und die Ver- 

 teilung der Sexualorganc. Bot. Zeit. 1881, p. 753. 



4 Flora 1878, p. 499. 



5 Reed has shown (Annals of Bot. 21; 501, 1907) that prothallia of G. sulphures 

 were unable to form archegonia where calcium was absent. Translator. 



