[Vol. 2 

 360 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



itat. The first Pyrenomycetes, according to his view, were 

 some of these depatriated red algae, losing their pigments 

 while preserving the structure, the sexual organs and the gen- 

 eral evolution. But he recognized no known member of the 

 red algae as a prototype of the Pyrenomycetes. Primitive 

 trichogyne-bearing algae gave rise to the red algae on one 

 hand, and to the Pyrenomycetes on the other, the now known 

 colorless red algae (like Uarveyella mirabilis, Choreocolax 

 alba) being recently reduced forms having no significance in 

 the origin of the sac fungi. But the Pyrenomycetes with well 

 developed trichogyne and spermatia are chosen as the primi- 

 tive forms, the simplest represented by Polystiyma (in his 

 "Polystigmales") the higher ones (his "Pyreniales") giving 

 rise successively to the llysteriales and Phacidiales. From 

 the Polystiy males three other lines arose, their simplest forms 

 being represented by first, Gymnoascus; second, Pyronema; 

 and the third line represented by the Laboulbeniales (see 

 Vuillemin, '12, pp. 338-341). 



Bessey ( 14) regards the Discolichenes as the most primi- 

 tive Ascomycetes. This theory is based on the supposed 

 phyletic relation of the multiseptate trichogyne of the lichens 

 (Collema, for example) to the trichogyne (a mere tubular, 

 continuous, prolongation of the egg) of the red algae. Cer- 

 tain of the red algae became parasitic on blue-green algae and 

 on simple members of the green algae, forming a lichen 

 thallus. It is supposed that this parasitism may have had 

 its origin while both kinds of organisms still lived in the water, 

 but finally the lichen assumed the land habit. The improba- 

 bility of such a derivation of the sac fungi as suggested in the 

 above theories has been fully discussed in the preceding pages. 



II. Descent f 



-De Bary ( '81, '84, 



'87), as already stated in the first part of this paper, be 

 lieved the Ascomycetes were derived from the Phy corny cetes, 

 particularly through such forms as the Peronosporales. The 

 criterion for the relationship is the close homology and mor- 

 phological resemblance of the sexual organs, though he sug- 

 gested that Eremascus might have been derived from the 

 Mucorales through some such form as Piptocephalus where 



