184 THE ASCOMYCETES 



which conidia are abstricted, is developed. After conidial pro- 

 duction ceases, these conidial stromata disappear, and the deeper- 

 seated hyphae develop pads of fungus tissue beneath the epi- 

 dermis. Within these pads are certain deeply staining cells, each 

 of which abjoint three or four daughter cells that become two- 

 to three-nucleate. Pairs of these cells fuse, and from the fused 

 cells ascogenous hyphae arise. 



The type of sexuality in Systreirmia iilmi is quite unlike that 

 recently described for S. acicola by Wolf and Barbour (1941). 

 This fungus forms coincidentally on dead needles conceptacles 

 of two kinds. In one, small rod-shaped spermatia are produced 

 in profusion from rows of spermatium mother cells. In the other, 

 several ascogonial coils occur, surrounded by loosely packed 

 nurse cells. The trichogynes project well above the surface of 

 the stromata. Presumably the spermatia lodge upon the tricho- 

 gynes and effect fertilization. About 6 to 8 weeks thereafter the 

 perithecia are mature, having been transformed from the locules 

 containing ascogonial coils. 



The conidial stage, Lecanosticta acicola, develops both on 

 green needles and on dry ones. Cultures isolated from conidia 

 produce conidia on artificial media. Furthermore cultures iso- 

 lated from ascospores produce the conidial stage on artificial 



media. 



The development of perithecia by Cymadothea trifolii [Wolf 

 (1935)] is quite like that described for 5. acicola. Both sperma- 

 tial and ascogonial locules may occur within the same stroma. 

 If moisture is available, the spermatia ooze out and lodge on the 

 several projecting trichogynes during the autumn. By the fol- 

 lowing spring the perithecia will have matured. 



The conidial stage, Folythrinciiim trifolii, possesses nodose, 

 wavy conidiophores, which were first noted about 125 years ago. 

 This wavy characteristic, a type of sympodial branching, arises as 

 the result of elongation of the conidiophore after each conidium 

 is matured and dislodged in succession. 



The mature stromata of Dothideales have been examined by 

 Orton (1924) and Blain (1927). Until more studies of similar 

 nature, involving a goodly number of species and elucidating de- 

 velopment of the stromata, have been made, exact knowledge of 

 this order is essentially non-existent. 



