1889.1 



BOTANICAL GAZETTE. 23 



In a preliminary communication 1 regarding his experiments in the 

 Tubingen laboratory on the effect of the lower oxygen pressure on the 

 movements of potoplasm, James Clark shows that when the pressure is 

 reduced to 1.2-3.0 mm. of mercury all movement quickly stops. 



C. Warnstorf, of Neuruppin, Germany, asks the directors of 

 herbaria and all bryologists to aid him with material for study of the 

 Sphagnaeeae of foreign countries. He promises to use submitted mate- 

 rial with the utmost care, and, unless otherwise specified bv the sender, 

 to return it after examination. He has in contemplation a Sphagnoh nia 

 Universa. As Warnstorf is already known as one of the most thorough 

 students of this perplexing group, we hope he will meet with a generous 

 response to his request. 



Stahl {B'.L Zeit. 1880) states that in Lemna trisulca the chloro)ln 11 

 grains, which in ordinary diffused light are ranged upon the two wallsof 

 each cell lying parallel to the frond's surface, at night are driven to the 

 side walls or lowest wall, leaving the superfic \ one bare. Mr. Spencer 

 Le M. Moore (Jour. But Dec), in his observations on the subject, differs 

 somewhat from these conclusions. His results show tint while many of 

 the grains are driven by darkness from the superficial to the side walls, 

 many of them still remain on the superficial wall. This subject of pho- 

 tolysis is a very interesting one, and observers having duck-weed con- 

 venient would find in it a profitable field of investigation. 



In the seventh part of the Proceedings of the German Botanical 

 Society (p. 248), Frank sums up his preceding observations and researches 

 on mycorhiza, which go to show that the fungus of mycorhiza acts as a 

 transporter of nourishment for the plant>. Mycorhiza is most widely dis- 

 tributed. Specimens of tree roots from the most diverse parts of the world 

 exhibit it, and the number of sorts of trees on which it has b( a found 

 is now very large.^ (In the proceedings of the same meeting is published 

 a piper by Alb. Schlicht, listing forty seven more species of herl>aceous 

 plants on which it occurs.) Mycorhiza is dependent for its development 

 on the presence of humus in the soil, and therefore the fungus can not 

 be a true parasite. The further facts that the roots at no time of year are 

 free from the fungus, that roots thus invested do not perish sooner than 

 others, and that cultivation experiments with beech seedlings >how them 

 poorly nourished without mycorhiza even in huniu itself, all gu to es- 

 tablish the symbiotic character of the association. 



Dr. Adam Prazmowski discusses in an address delivered before the 

 biological section of the Congress of Polish naturalist ' the nature and 

 function of the root tubercles of the Legumincw \ He has been unable to 

 confirm Ward's observations as to the nature of the "baeteroid" bodies 

 and the fungus itself. He considers that the tubercles are due to the at- 

 tack of a special organism which may be Baid to 1 long to the fungi in 

 the widest sense, but is not a hvphal fungus ; Hvphenpilz), althovmh in 

 its youn^r stage it occurs in the form of hypha-like filaments, which col- 

 lectively form a sort of mycelium. It do \s not possess the characteristic 

 membrane of the fungi, and in its older stages forms a sort of Plasmo- 

 dium. In many ways it approaches such Myxomycetes as Plasmodioi 

 phora Brassiere. As to the bacteroid bodies themsdv , Prazmowsk- 

 hinks that they can not be germ because he has observed the forma- 

 tion of spores in the older and injured tuberc'es only, and becau these 



'Berichte d. deutsch. b< <Jesel vi. 273. 



*See the Rotemisches Cencralblatt xxxvi, 215, 248, 280. 



