A Study of Meadow-Crop Diseases in New York 17 



cultures and found that they varied from 22.4 to 37.7 /x by 19.1 to 27.4 ft. 

 The writer's measurements fall within the latter limits. 



The name of the fungus has been juggled somewhat in the literature 

 because of a misunderstanding of the perfect stage and because of the 

 confusion of the two fungi on clover and alfalfa. Gentner (1918) reports 

 perithecia of Pleospora herbarum Rabenh. in pure cultures of a fungus 

 which he identified as M. sarcinaeforme. Marchal and Marchal (1921) 

 state that Pleospora lycopersici n. sp. is the perithecial form M. sarcinae- 

 forme. Krakover (1917:279) concludes that the fungus on red clover is 

 different from that on alfalfa because the conidia of alfalfa are much 

 smaller and decidedly warty, whereas he had never seen any but smooth 

 spores from red clover. Gentner (1918) also finds some slight morpho- 

 logical differences between the fungi on the two suscepts; but since conidia 

 from different varieties of alfalfa also differ, he concludes that the two 

 are identical. Tehon and Daniels (1925:717) following Elliott's (1917:471) 

 suggestion that the fungus is not a good member of the genus Macro- 

 sporium, and assuming that the forms on clover and alfalfa are identical, 

 erect a new genus, Thyrospora, with T. sarcinaeforme (Cav.) comb. nov. as 

 the type species. The chief character of Thyrospora is the echinulate or 

 warty conidia. 



The investigations of the present writer seem to shed some light upon 

 this nomenclatorial tangle. In connection with laboratory tests of fungi- 

 cides more than 250,000 spores produced in pure cultures from red clover 

 were examined with the low power of the microscope. Not a single spore 

 with spiny walls was ever seen. Numerous supplementary observations 

 of both stained and unstained spore walls with the high power of the 

 microscope and with oil-immersion objectives have substantiated this 

 conclusion. Spores from lesions on alfalfa leaves invariably appear 

 obviously roughened. Examination of specimens of these fungi on clover 

 and alfalfa from Illinois, which were sent to the writer by Dr. L. R. Tehon, 

 revealed that the spores from the clover leaves are smooth, whereas spores 

 from alfalfa leaves are spiny. 



Furthermore, the leaf lesions on the two suscepts are different. Those 

 on alfalfa contain much more yellow than those on red clover, although 

 this may be a suscept response. Single conidial cultures from the two 

 plants grown under identical conditions are distinct, as shown in figure 3. 

 Cultures from red clover are velvety black, with practically no aerial 

 mycelium and no signs whatsoever of perithecial formation. Smooth- 

 walled conidia are produced in great profusion. Cultures from lesions 

 on alfalfa leaves, on the other hand, are very much lighter in color, possess 

 none of the velvety black character, have white fluffy aerial mycelium, 

 with but little dark-colored submerged mycelium, and bear only a few 

 conidia that are spiny. These cultures produce a limited number of black 

 sclerotioid bodies which appear to be perithecial primordia. Incidently, 



