TRICHODERMA LIGNORUM 



175 



lignorum, confirming those just described, were made by the author 

 with the assistance of Miss Ruth Macrae in the autumn of 1927. 

 Some conidia obtained from a green conidial mat found on rotting 

 wood at Winnipeg were sown in a hanging drop of malt-agar. 

 They germinated readily and each one gave rise to a myceUum 



Fig. 99. — Trichoderma lignorum. Germination of spores (conidia) on 

 malt-agar and the non-sexual fusion of monosporous mycelia : 

 a, spores just placed in the medium : b—l, drawn 16-17 hours 

 later ; m and n drawn 24 hours later ; b, a swollen spore ; 

 c, d, e, spores developing germ-tubes ; f-k, young monosporous 

 mycelia ; /, two monosporous mycelia, the one on the right by 

 means of a hypha is about to touch and to unite with the swollen 

 spore of the other ; m and n, two compound mycelia, formed by 

 tiie fusion of two and of three simple monosporous mycelia re- 

 spectively. Drawn by A. H. R. Buller and Ruth Macrae. Mag- 

 nification, 466. 



filled with fine protoplasm (Fig. 99, a-k). Where two or more 

 mycelia were formed close together in the medium, they soon fused 

 (Fig. 99, l-n). In one instance (Fig. 100) seven spores produced 

 as many simple monosporous mycelia which fused together to form 

 one large compound mycelium. This compound mycehum was 

 entirely submerged in the agar medium. Ultimately, one of the 

 monosporous mycelia (Fig. 100, a), which happened to be near the 

 surface of the agar, gave rise to a conidiophore (6) which pushed 

 its way into the air and produced balls of green conidia (c). The 



