370 BROOKLYN BOTANIC GARDEN MEMOIRS 



3. Pnccinia Centaureae (Mart.) Hasler. 



a. Scahiosae on Centaur ea scahiosa. 



b. Nigrae on Centaur ea nigra. 



c. Nervosae on Centaur ea nervosa. 



d. Transalpinae on Centaurea transalpina, C. alba, C. austriaca, 



C. Jacea var. longijolia, C. nervosa, C. nigrescens and C. 

 phrygia. 



Puccinia chaerophylli Purt. Semadeni (139, 140) claims that a 

 race of this rust occurs on Anthriscus silvestris and another on Chaero- 

 phyUiim aiireum. 



Puccinia Epilobii-tetragoni (DC.) Winter. Dietel (29) was unable 

 to infect Epilobium hirsutum with aecidiospores from E. tetragonum. 

 This is the only indication of specialization in this rust. 



Puccinia Geranii-silvatici Karst. This rust has been reported on a 

 few species of Geranium in widely separated localities. It occurs 

 commonly on Geranium silvaticum in Europe. Its restriction to widely 

 separated regions has led to the suggestion that the rust consists of 

 geographically specialized races. Jacob (66, 67) has shown by cul- 

 tural experiments that there is no specialization in Europe, for both 

 Geranium silvaticum and G. rotundifolium are readily infected by 

 teleutospores from the former. 



Puccinia Helianthi Schw. Arthur, Kellerman, and Jacky have 

 made inoculation tests using teleutospores of this rust. Jacky (65), 

 using teleutospores from Helianthus annuus, infected 'H. annuus, H. 

 cucumerifolius , and H. calif ornicus , but failed to infect H. maximiliani, 

 H. midtiflorus, H. rigidus, H. scaberrimus and H. tuberosus. 



Kellerman (74, 75) obtained negative results with teleutospores 

 from H. annuus on eighteen species of Helianthus. His results with 

 teleutospores from H. ambigiius were negative on twelve species and 

 also negative with teleutospores from H. decapetalus on eight species. 

 He found, however, that teleutospores from H. mollis infected H. 

 annuus and H. mollis but not fourteen other species; teleutospores 

 from H. grosse-serratus infected H. annuus, H. decapetalus, H. giganteus, 

 H. grosse-serratus, H. Kellermani, H. orygalus and H. track eifolius, 

 but not H. maximiliani nor H. mollis; teleutospores from H. tuberosus 

 infected only H. annuus. 



Arthur (3, 4, 5, 6) secured the following results: (i) Teleutospores 

 from Helianthus mollis infected H. annuus, H. hirsutus, H. mollis, 

 H. occidentalis, H. strumosus and H. tomentosus, but not H. grosse- 

 serratus, H. Kellermani, H. laetiflorus, H. longifolius, H. orygalus and. 

 //. tuberosus; (2) teleutospores from H. grosse-serratus infected H. 

 annuus, H. grosse-serratus, H. maximiliani and H. tomentosus but not 

 H. decapetalus, H. hirsutus, H. laetiflorus, H. mollis, H. occidentalis, 



