616 Graham : Conocephalum conicum 



The gametophore of Conocepliahmi conicum begins to develop 

 early in June. The archegonia are ready for fertilization about 

 the first of July. The sporogonia develop rather slowly but the 

 spores and elaters are fully .formed by the time winter sets in, 

 when growth ceases. At this time the stalk of the gametophore 

 is very short, so that the conical receptacle appears to be sessile 



r 



on the thallus. During^ the warm days of the following 



May 



stalk of the gametophore elongates with some rapidity, lifting the 

 receptacle high above the surface of the thallus. The stalk of the 

 sporogonium itself then elongates, after which the spores are set 



free by the rupture of the capsule, * 



Each archegonium is developed in a flask-shaped cavity or 

 depression on the under side of the archegoniophore. Usually 

 only one archegonium appears in each depression, but rarely two 

 may be found. The archegonium arises from and is attached to 

 the tissue at the base of the cavity in which it is developed, but 

 the neck of the mature archegonium projects through the circular 

 opening of this depression and curves upward toward the lateral 

 margin of the gametophore {^Jigure jy). At the time of fertiliza- 

 tion the wall of the venter is about two layers of cells in thickness 

 {figures /, (5, J7). 



The fertilized ^^^ enlarges until it nearly or quite fills the 

 oblong cavity of the venter [figure A and becomes enveloped by 



^ Note, — The first material was put up in May, I908, when the sporogonia were 

 mature on elongated stalks, and in the beginning of June when there was evidence that 

 the archegoniophores were beginning to develop at the tips of the new thalli. Begin- 

 ning with July 14, I908, until August 10, 1908, material collected at Ithaca was care- 

 fully packed in moist sphagnum and shipped to New York City where it was kept in a 

 moist vigorously growing condition until it was needed. Collections were made from 

 this material two or three times weekly until September 21, 1908. 



All the material used for this work was fixed in chrom-acetic fixing fluid. The 

 gametophores were fixed entire. In all cases care was taken to remove the air from 

 the tissue. For the material put up at Ithaca the large air-pump in the laboratory was 

 used, but for the material fixed elsewhere a small suction pump attachable to a faucet 

 was found as effective as the large air-pump. This treatment of the tissue was neces- 

 sary for, as is well known, the thalli and gametophores of all the Marchantiaceae con- 

 tain air which prevents the entrance of fixing fluids as well as other reagents, especially 

 those used in infiltrating and embedding. 



All the sections were cut 8-10 /i in thickness, except those of the mature sporo- 

 gonium containing genninated spores; these were sectioned 5// thick- The sections 

 were stained with Delafield's haematoxylin alone or with a counterstain of Bismarck 

 brown* 



