Nov. 15,1920 Crownwart of Alfalfa Caused by Urophlyctis alfalfae 313 



boiled with caustic potash and cleared with chloral hydrate, reveal a ring 

 of pits altogether similar to those observed on spores of U. alfalfae and U. 

 pluriannulatus . That this implies the presence of haustoria in the fol- 

 lowing species can hardly be doubted: 



Urophlyctis bohemica Bubak on Tri folium montanum, Rabenhorst- 

 Pazsche, Fungi Europaei et extraeuropaei, No. 4378. 



Urophlyctis kriegeriana Mag. on Carum carvi, Jaap. Fungi sel. exs. 

 No. 126. 



Urophlyctis kriegeriana Mag. on Pimpinclla nigra, Bubak, F. Fungi 

 Bohemici June 9, 1901. 



Urophlyctis magnusiana Neger on Odontites rubra, Vestergreen, Mic. 

 rar. sel. No. 1614. 



Urophlyctis major Schroeter on Rumcx britannica, Davis, J. J., Wiscon- 

 sin fungi. Aug. 27, 1 91 3. 



Urophlyctis pulposa (Wallr.) Schroeter on Cheno podium glaucum, Sydow 

 Myc. ger. No. 1086. 



Urophlyctis rubsaamcni Magnus on Rumex scutatus, Jaap, O Fungi 

 sel. exs. No. 402. 



Seventeen species of Physoderma and Cladochytrium were also exam- 

 ined by the same method, and of these at least 2 species — namely, Physo' 

 derma menthae Schroeter on Mentha aquatica, Vestergreen, Mic. rar. 

 sel. No. 1609, and P. zeae-maydis on Zea mays, material furnished by 

 W. H. Tisdale — revealed a zone of pits, although no direct evidence could 

 be obtained that these had served as places of attachment for haustoria. 

 It is interesting to note that a certain range in number of pits was found 

 to be characteristic of species and that even numbers seemed to predomi- 

 nate. Thus Urophlyctis rilbsaameni showed either 6 or 8. Pronounced 

 and constant disparity in number of pits may, indeed, be interpreted as 

 indicating rather clearly that forms assigned to the same species because of 

 close relationship of their hosts may belong to quite different species. It 

 appears hardly admissible, for example, to designate the parasite on Pim- 

 pinclla nigra with 10 to 14 pits as U. kriegeriana, when this species of 

 Carum carvi shows only from 6 to 10; and the identity of U. kriegeriana 

 and U. pluriannulatus, suggested by Farlow (7) as a fair possibility, would 

 seem to be equally improbable. 



In a number of species as, for example, Physoderma maculare (5), 

 P. butmio (4), and P. zeae-maydis (33), the germination of the resting 

 sporangium involves the lifting off of a circumscribed portion of the 

 spore wall by the expanding endosporangium. Although this "lid" is 

 usually not apparent in the spore wall, its presence on the resting 

 spores of P. comari, P. eleochardis, P. gerhardti, P. iridis, P. menthae, 

 P. schroeteri, P. vagans, and P. graminis could be determined from an 

 examination of herbarium material with moderate certainty. It remains 

 a question whether the resting spores of those species in which nothing 

 resembling a lid could be made out, including for example, P. agrostidis, 



