168 DopGE: RELATIONSHIPS OF FLORIDEAE AND ASCOMYCETES 
be gained is primarily to reach the surface, just as it is in the species 
of lichens described by Stahl (Fic. 1, A and B). 
The most obvious difference between the Ascomycetes and 
red algae is found in the absence in the latter of anything like free 
cell formation. The ascus is the most characteristic and unique 
structure of the Ascomycetes. As De Bary and most of the 
earlier students of the group recognized, the process of free cell 
formation as found in the ascus is typically different from any 
Fic. 4. Procarpic branch and outgrowths from the carpogonium in the red 
algae. A. Halymenia ligulata; B. Batrachospermum moniliforme; C, D, Erythro- 
phyllum delesserioides; E. Harveyella mirabilis; F ; 
thamnion Plumula. aux, auxiliary cell; c.c, central cell; cp.br, carpogenic branch; 
cpg, carpogonium; csp, carpospore; f.c, fusion cell; g, gonimoblast; o.f, odblastema 
filament; spm, spermatium; tr, trichogyne. A, Bornet; B, Davis; C, D, wiss; 
E, Sturch; F, G, Daines; H, Phillips. 
other method of spore formation known in the fungi. And the 
morphological characters of the ascus constitute the main difficulty 
in all attempts to derive the Ascomycetes from the Florideae- 
Recent cytological studies (Harper, 51) have emphasized the 
differences between free cell formation and the progressive cleavage 
found in sporangia, and Dangeard’s discovery of nuclear fusion in 
