The Origin and Development of the Apothecium etc. 373 
somewhat above this. Following De Bary (27), Stahl called this entire 
structure a carpogone, the coiled basal portion he called the ascogone, 
and the long terminal filament the trichogyne, a name which had 
originally beeil given by Bornet and Thuret (12) to a similar structure 
in the red algae. Stahl apparently made a very careful study of his 
preparations and has given quite a detailed account of his observations. 
In Collema microphyllum the ascogone consists of two and one half to three 
c-oils, and of a varying number of cells averaging twelve. The trichogyne 
cells are narrower than those of the ascogone, of different lengths, and 
vary in number with the length of the trichogyne. The end cell of the 
trichogyne, which projects somewhat above the surface of the thallus, 
is covered with a sticky substance, to which the spermatia as well as 
particles of foreign material adhere. The small rodlike spermatia, the 
ends of which are somewhat thickened, are extruded in large numbers 
from the neck of the spermogonium in which they are borne and are 
probably spread over the surface of the thallus by means of rain-drops. 
Stahl finds that the spermatia become attached very firmly to the tricho- 
gyne so that neither water nor a jarring of the cover glass will detach 
tliem. He has figured three cases in which the wall has been dissolved 
between the spermatium and the trichogyne, resulting in a continuity 
of the protoplasm of the two cells. After this fusion, the cross walls 
of the trichogyne become niuch thickened in the direction of the longi- 
tudinal axis of the filament. The content of these cells is now brown 
and in marked contrast to the thick, pale swellings of the cross walls. 
The cells of the ascogone now grow and become more numerous. This 
makes a sharp line of demarcation between trichogyne and ascogone. 
For a time the ascogone is not branched. The tangle of hyphae surround- 
ing it becomes denser and from this extern! many upright parallel fila- 
ments which form the Anlage of the hymenium. The proper exciple is 
pseudoparenchymatous and arises from filaments resembling paraphyses. 
From the ascogone, as Janczewski (56) had described for Ascololus 
and Kihlman (57) for Pijronema, come the ascogenous hyphae. These 
are septate and their cells vary greatly in width and length. Often the 
same cell is much swollen at one end and drawn out to a filamentous 
structure at the other end. The asci arise as outgrowths from the as- 
cogenous hyphae. 
In the other species of Collema which he investigated, Stahl found 
a great similarity in the development of the apothecium to that described 
for C. micmphyllum. In Synechoblaslus, he found the ascogone not a 
regulär spiral, but made up of irregulär windings. In Physma compactum 
