v] 



SPHAERIALES 



i59 



rotia which originate in the cortex of the host root; reproduction is by 

 means ot conidia formed in summer on the surface of the soil, and further 

 by ascospores produced in perithecia, I [artig has found that the perithecium 



is initiated by the development of a pair of thick hyphae rich in contents. 

 These become enclosed within a mass of vegetative tissue, but their subse- 

 quent behaviour lias not been determined, and no details of development 

 are known either here or in other members of the family. 



SPHAERIACEAE : BIBLIOGRAPHY 



• HARTIG, R. Der Eichenwurzeltodter Rosellina quercina. Untersuch. aus der forst- 

 botanische Inst, zu Miinchen iii, p. 1. 



Ceratostomataceae 



The Ceratostomataceae resemble the Sphaeriaceae in most of their 

 characters: they are distinguished by the elongated neck of the perithecium, 

 which is often drawn out to form a delicate hair-like process. The method 

 of liberation of the spores in this family presents an interesting problem, 

 but neither that question nor the development of the perithecium has yet 

 been elucidated. 



A mphisphaeriaceae 



In the Amphisphaeriaceae the young perithecium is sunk in the substra- 

 tum; as it matures it becomes more or less free, though in contrast to the con- 

 dition in the Sphaeriaceae and Ceratostomataceae, its base is always immersed. 



Development has been studied in a species of Teichospora and a species of 

 Teichosporella, now both included 



under the genus Strickeria, charac- 

 terized by its muriform spores. 

 The spore produces numerous 

 germ-tubes which give rise to a 

 mycelium of multinucleate cells ; 

 certain cells increase in size and be- 

 come both transversely and longi- 

 tudinally divided till a parenchy- 

 matous mass is produced (fig. 1 19). 

 Other vegetative hyphae may fi >rm 

 a scanty investment, but often the 

 perithecium develops without this 

 addition. 



Asci appear as large uninu- 

 cleate cells, and the tissue around 

 them disorganizes. The outer hy- 

 phae become hard and dark only 

 when the perithecium approaches maturity 



Fig. 1 11;. Shi keria sp, ; initial cells of ascocarps : 

 after Nichols. 



