CLASS ASCOMYCETEAE 267 



in Ophiostoma fimbriatum (E. & H.) Nannf. (Ceratostomella) there arise 

 uninucleate oogones on short stalks and drawn out into a trichogyne with- 

 out nucleus or separating septum. From the same or from a nearby hypha 

 arises an antheridial branch which coils around the oogone and tricho- 

 gyne. The uninucleate upper cell makes an opening into the trichogyne 

 through which the male nucleus passes and proceeds downward to the 

 body of the oogone, enlarging as it goes. As a result of numerous nuclear 

 divisions occurring conjugately many pairs of nuclei arise which pass out 

 into nonseptate ascogenous hyphae. In the meantime the hyphae below 

 the oogone have growm outward and upward to form a closed perithecium 

 with a thin dark-colored external wall and a mass of hyaline, thin-walled 

 cells to which the ascogenous hyphae attach themselves and from which 

 they grow into the perithecial cavity and produce their asci, apparently 

 without crozier formation, scattered at random through the central hol- 

 low. Eight ascospores arise in each ascus and ascus walls, ascogenous 

 hyphae and the remainder of the "nurse cells" digest. In the meantime 

 the long perithecial neck has developed and finally opened at the end 

 permitting the mucilaginous mass of ascospores and digested cell walls to 

 exude as a drop. Gertrud Mittmann (1932) investigating the same fungus, 

 contrary to Elliott's report failed to find any antherid. According to her 

 the ascogonium begins as a single, uninucleate somewhat curved terminal 

 cell of a short lateral branch. The cell elongates and coils into several 

 turns, dividing into three to five uninucleate cells. From the supporting 

 cell, enveloping hyphae begin to grow and eventually give rise to the 

 perithecial wall. Miss Mittmann suggests that the antherid reported by 

 Elliott was one of these enveloping hyphae. When this envelope is several 

 cells in thickness the ascogonial cells enlarge and separate somewhat. One, 

 or sometimes two, of these enlarged cells becomes multinucleate, the 

 number of nuclei usually being eight. This cell (the oogone) divides into 

 several cells which also become eight-nucleate and then divide into bi- 

 nucleate cells which thus form a richly branched system of crowded cells 

 in no definite order. These cells enlarge laterally and their nuclei unite, 

 thus forming the young asci which are nourished by the plasma-rich 

 projecting cells of the inner layer of the perithecial wall. The ascospores 

 are surrounded by a slime layer. 0. coeruleum (Miinch) H. and P. Sydow 

 (C. coerulea Miinch) and 0. pluriannulatum (Hedge.) H. and P. Sydow 

 (C pluriannulata Hedge.) are reported by Miss Mittmann to be quite 

 similar in development but each falls into two sexual strains, both of 

 which must be present in order that perithecia shall be formed. If she is 

 correct in her statements that no antherid is present a union of hyphae at 

 some other point seems to be indicated. Sartoris (1927) found no antherid 

 near the coiled ascogonium of 0. adiposum (Butl.) Nannf., studied by 

 him. Varitchak (1931) found in 0. piceae (Miinch) H. and P. Sydow a 



