110 MASSACHUSETTS HOKTICULTURAL SOCIETY. 



■which cause the diseases known as aiithracnoses. "While there 

 are probably groups of species included in tliese form genera, 

 which if they have a perfect form would be found to belong not 

 only to different genera of ascomj'cetes, but even to different 

 families of fungi, there seem to be species so closely allied that 

 together with the fact that they can in one way or another pass 

 the winter or unfavorable periods for growth, they suggest a like 

 origin from the same perithecial form. The colletotrichum of 

 the bean can live in diseased seed beans and start the disease 

 anew when the seedlings begin to grow. The cotton colletotrichum 

 lives on the seed, either by the vitality of the conidia or from 

 stromatic bodies, so that the disease can be originated at the 

 beginning of the season bj^ simply planting seed Avhich comes 

 from diseased bolls. In the case of the gloeosporium of the 

 privet, G. cingidatnm, the mycelium is perennial in the diseased 

 stems, and breaks out on the advent of spring again. In many 

 of the species stromatic bodies are developed Avhich would assist 

 them in hibernating. 



Artificial cultures of certain of the polymorphic fungi belong- 

 ing to the Pyrenomycetes show that at least under these condi- 

 tions imperfect forms are usually slow to develop a complemental 

 ascosporous form, though this is by no means general, while 

 the ascosporous form can usually quite readily be grown into the 

 conidial form. Some cultures which I carried on with Nectria 

 cinnahaHna, a very common fungus found on a great variety of 

 twigs and dead limbs, and by some supposed to be quite a serious 

 parasite at times, illustrate this. The culture was started from 

 the ascospores of the fimgus found on dead stems of sambucus 

 (elder). Sown in niitrient agaragar the ascospores germinated, 

 but grew slowly, forming small colonies by the side of large ones 

 of different saprophytic fungi which appeared in the culture. On 

 transplanting some of the colonies to sterilized bean stems in 

 culture tubes, the characteristic stroma and conidia of the tuber- 

 cularia stage appeared, but after keeping the cultures for nearly 

 a year and making several transfers, no ascosporous form 

 appeared. I would not infer from this that the perfect form 

 could not be produced from the imperfect form in artificial cult- 

 ures, for I believe that it could if advantage Avere taken of the 

 right conditions. ]>ut it is a difficulty whieli has been encountered 

 by others, and in the case of other species, and shows probably 

 in nature also, so far as we can judge from observation, that the 



