230 BOTANICAL GAZETTE. 



differ from all previously described ones in being attached to the cell-wall by 

 several pedicels and in the absence of calcium carbonate. Their reactions in- 

 dicate that they are composed of slightly lignified cellulose. 



F. Ludwig calls attention in Kosmos to the flower of one of the Aroidese 

 (Phi/ml, ndron bipinnatifidum) , whose structure is such as to fit it for fertilization 

 by snails, which, attracted by a strong nutmeg odor, creep into the spathe and 

 crawl about over the flowers. The snail is certainly the last animal to be sus- 

 pected of any connection with the cross-fertilization of flowers. What next? 



The meeting of the American Association of Science at Minneapolis next 

 August will give an admirable opportunity for botanists to become acquainted 

 with an interesting flora. Probably the first plant to attract attention upon ar- 

 riving in the city is the northern wormwood, Artemisia frigida, with delicate 

 whitened foliage clothing the rocks and banks below the Falls of St. Anthony. 

 The other flowering plants meriting attention are numerous. The region is also 

 rich in Characem and other fresh-water algfe, especially Nostocacea and Desmidea: 

 The long excursions will doubtless go into districts of still more unfamiliar 

 vegetation. The meeting should command a larger attendance of botanical 

 students and collectors than heretofore. 



The theories in regard to the structure and growth of the cell-wall are 

 having a thorough overhauling at the hands of German histologists. A resume 

 of Prof. Strasburger's last work, in which he criticises the generally-received 

 Nicgelian hypothesis, has already been given (vide. p. 172, this volume). In 

 addition, now comes F. Schmitz, who adduces further arguments from the struc- 

 ture of the cell-wall in the filamentous alga', in support of his view that the 

 growth of the cell-wall in surface as well as in thickness is due to apposition 

 and not to intussusception. Von Hohnel, after examining the wall of bast- 

 fibers and other cells, comes to the conclusion that the wall is not composed of 

 crystalline micella?. All the phenomena exhibited by cell-walls with polarized 

 light he believes can be explained by a simpler theory, and one which also ex- 

 plains some phenomena of swelling up of ihe wall not hitherto explicable on 

 the micellar hypothesis. (See But. Zeit. xl, pp. 595 and 616, for an account of 

 his theory of molecular tensions.) While the discussion is thus running it will 

 be well for teachers and lecturers to hold lightly to the Na'geli an theory of 

 micelhe at least, and possibly also to that of intussusceptive growth. 



It seems that the effect of free oxygen upon quiescent bacteria is so great 

 that the presence of the trillionth of a milligram of the gas can be detected by 

 their movements ; and this fact is being applied in the study of the work of 

 assimilation in relation to various colors, one result of which is to show that 

 there must be a series of colors other than that of chlorophyll which possess the 

 power of assimilation. 



It is not considered good taste to apologize for one's own appearance, but 

 the April Gazette must be our excuse. We are to be congratulated that it 

 made its appearance in any shape, for it fell into most incompetent hands. Hav- 

 ing now contracted with a firm conceded to do the best work in the State, it is 



