FUNGI IMPERFECTI 



323 



no anthracnose. In general, it should not be taken to indicate that 

 such seed will remain free from the disease. 



The fungus attacks pods, stems, and leaves, but the most con- 

 spicuous injuries are the spots upon the pods (Fig. 154). These 

 appear first as small, brownish, 

 or purplish discolorations, and 

 as the fungus spreads radially 

 the central portion becomes 

 dark and sunken. Neighbor- 

 ing spots may also coalesce, so 

 that irregular sunken patches 

 may result. The conidia in 

 quantity have a pinkish tint, 

 and the ulcerated areas develop 

 the spores so profusely that 

 this color becomes pronounced 

 under favorable conditions. 

 The fungus may appear upon 

 the cotyledons or young hypo- 

 cotyls of the seedlings, and 

 this is usually indicative of 

 badly affected seed. 



The fungus. The mycelium 

 penetrates the affected parts 

 to a considerable extent. The 

 bean seeds beneath the lesions 

 on the pods are commonly 

 spotted or slightly discolored, 

 and a careful examination 

 would show that the fungous 

 hyphae are also present in 

 those parts. Distribution of the 

 fungus another year is insured 

 through such infected seed. 



Beneath the cuticle or epidermis of the older spots a stromatic 

 mass of hyaline hyphae is developed, and from this arise numer- 

 ous short conidiophores bearing the irregularly elliptical conidia 

 (F*ig. 156). Near the margins of these spore pustules, or accrvuli, 



;4. A\ in K ICNOSE <>K I'-i \NS 

 (Photograph by II. II. Whetzel) 



