548 



THE FUNGI WHICH CAUSE PLANT DISEASE 



Spots subelliptic to irregular, depressed, brownish; acervuli 

 scattered, surrounded by a few not very conspicuous black setfe; 

 conidia oblong, ends rounded, straight or curved, 15-19 x 3.5-5.5 

 ft; conidiophores cylindric, simple, 45-55 fi. 



This fungus, generally known as C. lindemuthianum, is accord- 



trittiniciuse Conhcr 



Starcfi Grains 



Fig. 369. — C. lindemuthianum. Showing relation of the fungus 

 to the tissues of the bean. To the left above is a diagram of 

 a section across a bean pod through a canker. The drawing 

 below is a much enlarged largely diagrammatic view of a por- 

 tion of this same section. It shows how the mycelial threads 

 of the fungus may penetrate the seed coat and enter the 

 starchy tissue of the seed, there to remain dormant until the 

 following season. On the left is a spore germinating and pene- 

 trating the epidermis. To the right a magnified view of spores, 

 one germinated. After Whetzel. 



ing to the cultural studies of Shear & Wood (see p. 267), probably 

 a variety oif Glomerella rufomaculans. See p. 264. 



On the bean it attacks stems, leaves, cotyledons, or the pods, 

 producing sunken spots of dead tissue which bear the numerous 

 pink acervuli. It has been shown that the mycelium on the fruit 

 may penetrate through the pericarp and into the seeds beneath 

 and there hibernate. 



C. lagenarium (Pers.) E. & H. "* is probably identical with 

 C. lindemuthianum. It is described as the cause of spots on fruit 

 leaves and stems of cucumbers, watermelons, squash, pumpkins 

 and citron. 



C. oligochsetum Cav. grows on cucurbs, attacking all parts.^^ 

 Probably=C. lindemuthianum. 



