PSEUDOPEZIZA 279 



to escape in the form of a viscid tendril. The spores forming 

 this filament or tendril are soon liberated by rain from the 

 viscid substance in which they are embedded, and are washed 

 on to other leaves, which in turn are infected. 



The ascigerous form of fruit is found in the spring on dead 

 leaves that have been lying on the ground during the winter. 

 The ascophore, like the spore-clusters, originates in the tissue 

 of the leaf and bursts through to the surface at maturity. 

 Spores, 8 in an ascus, broadly elliptical, hyaline, about 10 x 

 6 ft. ; paraphyses clavate. 



Dilute Bordeaux mixture or potassium sulphide checks the 

 extension of the disease. Rake together and burn fallen 

 leaves. 



Klebahn, 'Unters. iiber einige Fungi Imperfect! und die 

 zugehorigen Ascdmycetenformen,' Zeitschr. fiir PJlanzenkr., 

 1 6, p. 65 (1907). 



Alfalfa leaf spot. Alfalfa (Medicago sativa, L.) is subject 

 to many diseases, amongst the worst of which is Pseudopeziza 

 medicaginis (Sacc.), which usually forms numerous small 

 brown spots on the leaves, which in consequence soon turn 

 yellow and fall. In some instances, and for some unexplained 

 reason, badly infected leaves show but slight signs of yellow- 

 ing. The stem is also sometimes attacked, the fungus form- 

 ing elliptical black spots, 1-3 mm. in length. The lower 

 leaves are attacked first, and when the pest occurs in abun- 

 dance the crop is much depreciated owing to the loss of 

 leaves, and consequent check on the development of the 

 entire plant. 



The fruit does not contain ripe ascospores until the minute 

 cushion-shaped ascophore has ruptured the epidermis. 

 Spores 8 in an ascus, elliptical, hyaline, 8-n X4-6 //-. 



Stewart states that the disease often appears in fields where 

 alfalfa has not previously been grown. He considers this 

 may be accounted for, in some cases at least, by the land 

 being strewn with soil from infected land, for the purpose of 

 securing inoculation with nodule bacteria. In other instances 

 the spores may be sown with the seed ; or finally, the spores 

 may be carried by wind. 



Stewart, French, and Wilson, N. Y. Agric. Exp. Stat., 

 Geneva, Bull. No. 305, p. 384 (1908). 



