June, 1904.] 
The Jacket Layer in Sassafras. 
193 
protoplasm and begin to degenerate when the embryo-sac is full}- 
formed. This jacket la}"er thus performs an important function. 
First its cells nourish the developing female gametophyte, and 
later, by their disintegration a further food supply 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 
microsporan giinn . 
As stated before, this jacket layer in the ovule must be regarded 
as purely a physiological tissue, being developed in various ways 
in different angiosperms. It may be entirely absent as in Sagit- 
taria and Liliuni ; it may be represented simply by 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 laj^er of dark-staining 
cells. To the last type belongs Aster novae-angliae, w’here 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 Embr3-o-sac and Embryo of 
Agrostemma githago. Ohio Nat. 3 : 365-369. 1903. 
2. Chamberuain, C. J. The Embryo-sac of Aster Novae-Angliae. Bot. 
Gaz. 20 : 205-212. 1895. 
3. Burns, G. P. Beitrage zur Kenntniss der Stylidiaceen. Flora 87 : 313- 
354. 1900. 
4. Biluings, P\ 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 b}^ 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 
