238 



ASCOMYCETES. 



ripening in the spring of the fourth year. Or, again, a 

 *' casting " of brown one-year-old needles may take place in 

 autumn. 



The disease is found everywhere, but in some parts {e.g. in 

 the forests of Saxony ^), it is exceedingly common and very 

 dangerous. The apothecia are developed as long, shining, black 

 swellings on the two under surfaces of the quadrangular needles 

 (Fig. 121). The club-shaped asci emit 

 thread-like spores with gelatinous coats. 

 The ascospores produce a strong germ-tube, 

 which grows inside the needles to an 

 intercellular mycelium without haustoria. 

 Browning and shrinkage of the cells of 

 attacked needles soon follow. The myce- 

 lium also penetrates into the cells of the 

 epidermis, and develops there a coil of 

 hyphae, which, under a black membranous 

 cover, forms an apothecium containing 

 paraphyses and club-shaped asci (Fig. 

 122). When ripe, the apothecia rupture 

 the overlying epidermis. Little black 

 pycnidia (spermogonia) may also occur on 

 diseased needles.^ On needles which have 

 been prematurely cast, only little spherical 

 apothecial knobs will be found. 



According to Hartig, the effects of this 

 fungus on the cells of attacked needles is 

 very interesting. If the disease of the 

 needles appears in autumn, the cells, which 

 at this time are void of starch, become 

 brown and die. If the disease attacks in May, when the 

 needles are rich in starch, their death ensues soon, but the 

 starch only disappears gradually from October onwards, as it 

 is used up by the fungus-hyphae. If the disease appears in 

 •spring, when starch-storage is just beginning, the cells already 

 attacked become quite full of starch, whereas the other cells of 

 the same needle remain empty. ■ 



^ Nobbe, Ber. d. sdchsisclies Forstvertinn Versammlung zu Schandan, 1891. 

 - Another ascomycetous fungus — Naevia piniperda Rehm — occurs alone or 

 together Nvith this species ; Rehm regards it as parasitic {Hedwigia, 1892, p. 302). 



Fig. 123. — Lophodermiiim 

 maerosporum on Spruce. 

 Oerminated ascospores ; 



■some have germinated 

 inside the ascus. (After 

 R. Hartig.) 



