THAXTER. — LABOULBENIACE/E. 93 



which arise by a peculiar process of budding from ascogenic cells, of 

 which there may be from one to four, usually distinct and eventually 

 free within the cavity of the perithecium. 



The ascogenic cells are developed from a carpogonium consisting 

 of a single axile cell which is fertilized by non-motile male bodies 

 (antherozoids) through the agency of a more or less highly developed 

 trichogyne from which it is separated by a second axile cell. After 

 fertilization the carpogenic cell divides by transverse septa (in ascer- 

 tained cases) into three cells, the middle cell becoming either directly 

 an ascogenic cell or dividing into from two to four such cells, while 

 the other two supporting cells eventually disappear. 



The trichogyne varies from a simple vesicular receptive promi- 

 nence, or short filament, to a copiously branched and highly developed 

 organ, the numerous free receptive tips of which may be coiled in 

 close and regular spirals. The trichogyne, the insertion of which is 

 usually terminal, disappears immediately after fertilization is accom- 

 plished, however highly it may be developed, its insertion becoming 

 lateral by the further development of the perithecium. 



The antherozoids appear to originate in two genera exogenously from 

 special branches. In all other genera they are produced endogenously 

 in antheridia, the form and position of which vary in the different 

 genera. The antheridia are either single specialized cells, which may 

 be more or less irregularly disposed or characteristically grouped, or 

 may consist of more highly developed multicellular bodies. In either 

 case the antherozoids are discharged through a terminal pore in the 

 form of roddike or nearly spherical masses of naked protoplasm. 



The sexes are commonly both present on the same individual, 

 usually so placed that self-fertilization is readily accomplished, or 

 may be completely separated on specialized individuals. In the latter 

 case of the members of any given spore pair formed in an ascus 

 and discharged simultaneously from the perithecium one produces a 

 male, while the other produces a female individual, thus insuring the 

 juxtaposition of the sexes at the new point of infection. 



The spores which may be formed in pairs within the asci, or less 

 definitely disposed, are of one general type, fusiform in shape and 

 divided by a more or less well defined septum into two parts, the rela- 

 tive position of which in formation is reversed in development, the 

 segment which is basal in relation to its position in the ascus becom- 

 ing distal in its relation to the growing plant resulting from its 

 germination. A well defined gelatinous envelope surrounds the spore 

 when mature, and develops with the growing plant to form a sac-like 



