June, 1904.] Tke Jacket Layer in Sassafras. 193 



protoplasm and begin to degenerate when the embryo-sac is fully 

 formed. This jacket layer thus performs an important function. 

 First its cells nourish the developing female gametophyte, and 

 later, by their disintegration a further food suppl}- is furnished to 

 the developing endosperm and embryo. By their rapid disinte- 

 gration there is also a decided increase of room in the ovule. 

 These processes correspond to the functions of the tapetum in the 

 microsporangium. 



As stated before, this jacket layer in the ovule must be regarded 

 as pureh^ a physiological tissue, being developed in various ways 

 in different angiosperms. It may be entirely absent as in Sagit- 

 taria and Lilium ; it may be represented simpl}- bj' disintegrating 

 cells in contact with the embryo-sac as in many monocotyls and 

 dicotyls ; it may have a development as in the examples just 

 discussed ; or it may be a highly specialized layer of dark-staining 

 cells. To the last type belongs Aster novae-angliae, where the 

 layer is described by Chamberlain (2) as consisting of cells with 

 dense protoplasm remarkably free from vacuoles. Stylidium (3) 

 and Lobelia (4), as well as many other genera of Sympetalae, 

 have highly developed jacket layers. 



1. Cook, M. T. The Development of the Embryo-sac and Embryo of 



Agrostemma githago. Ohio Nat. 3 : 365-369. 1903. 



2. Chamberlain, C. J. The Embryo-sac of Aster Novae-Angliae. Bot. 



Gaz. 20: 205-212. 1S95. 



3. Burns, G. P. Beitrage zur Kenntniss der Stylidiaceen. Flora 87 : 313- 



354. 1900. 



4. Billings, F. H. Beitrage zur Kenntniss der Samenentwickelung. 



Flora 88 : 253-318. 1901. 



MEETINGS OF THE BIOLOGICAL CLUB. 



TowNSHEND Hall, March 7, 1904. 



The meeting was called to order by the President, Mr. Sanders, 

 and the business meeting was dispensed with. The paper of the 

 evening was given by Dr. Bleile on " The Anti-bodies." Much 

 interest was shown in the lecture and a large audience was present. 



Orton Hall, April 9, 1904. 



The meeting was called to order by President Mr. Sanders. 



Prof. Kellerman reported inoculations with rust on corn. He 

 experienced great difficulty in procuring good host plants on 

 account of the cold weather. He secured uredospores on pop- 

 corn inoculated with spores of Puccinia sorghi from sweet -corn. 



Prof. Hine spoke on the Gulf Biological station in Louisiana. 

 The station is located on the coast, at the mouth of the Calcasieu 



