GYMNOSPOR ANGI UM. 



385 



Experimental infection with teleutospores of Gymnoq-ior- 

 arujivm davariacforme from Jnnipcriis communis gave the fol- 

 lowmg results : 



-i 



Spore-fonii. 

 (?) - 



R. lacerata, - 

 lacerata, - 



On Host-plant. 

 Crataegus Oxyaeantha, - - - ] 

 Pyrus communis, 

 Crataegus tomentosa, 

 Crataegus Oxyaeantha, 



„ monogyna, 



Pyrus commtinis, - - . . Roestelia (?), - 

 Pyrus torminalix, . - - - pyciiidia, 

 Pyrus Malus, ----- „ 



Amelanchier, - - - - -It lacerata x, 



lacerata and aecidia 



Authority. 

 Plow right. 

 Thaxter. 

 Eathav. 



Oersted. 

 Thaxter. 



Crataegus Oxyaeantha, 



Crataegus grandifiorus, 

 „ sanguinea, 



„ nigra, 

 Cydonia vulgaris, 

 Pyrus Aucuparia, 



Pyrus latifolia, 

 Cydonia vulgaris, 



Crataegus nigra, 



CrataegxLS Douglasii, 



Pyrus Aria, 



Pyrus Aucuparia, - 



Pyrus communis. 



ill li 



\ wi 



:U 



th long tube-shaped -Tulieuf. 

 j)eridia, - - - | 



lacerata^ - - - 



littk 



aecidia 



- only pyenidia, 



- only pycnidia, 

 (pycnidia and 

 (^ aecidia, 

 [pycnidia and 



- -| with long tube-shaped J-Peyritsch. 

 y peridia, - - - ; 

 Jpycnidia and little ) 

 t aecidia, - - - I 



- only leaf-spots, - - „ 



- no result, . . - j, 

 .'pycnidia and aecidia with "j 

 ( a long peridium, j 



Note. — Before the relationship of the teleutospore-forms was known, the 

 aecidia were designated respectively : RoesttUa lactrata on Crataegus, R. rornula 

 on Pyruii Aucuparia, and R. peiicillafn on Apple. 



The most abundant germination of sporidia takes place on 

 species of Crataegus, and pycnidia (spermogonia) may make 

 their appearance within fourteen days after infection on little 

 yellowish sticky spots on leaves and shoots. By the time conidia 

 (spermatia) have made their appearance, deformation may be 

 far advanced. I did not succeed either in procuring germination 

 of the conidia, or infection by means of them. 



