PERENNIAL SPECIES. 27 



iiu'ubiition period is shortor if inoculatino- nmtorial is taken from liv- 

 iiio- plants, and duritifr the siiniiner it is prolnibly about the same as 

 that of infections from uredosi)ores. 



Numerous experiments were also made with other lepto species, 

 mchuWno; Piiccima <jrhidelhv,Vk.. l\ mnolam.W'AxV.. J*. Ii/yoihsmix^ 

 E. and E., and P. ii/ienirdia/ia, Korn, with residts similar to those 

 above mentioned. The writer has already called attention to the 

 phenomenon of the formation of catenulate sporidiola in two of these 

 species. /'. iirhuleihi' and l\ carioUutK." 



PERENNIAL SPECIES. 



The chance for the continued existence of a rust throug-h winter 

 resistance of the uredo without the intervention of another stai»e has 

 been discussed. Thouoh such a condition can only exist on a peren- 

 nial host, or at least one that lives over winter, it nuist not be sup- 

 posed that the fungus itself is necessarily or even usually perennial. 

 As fast as the leaves of the host die the spores simply drop on to the 

 next lower and younger leaves and produce reinfection, the mycelium 

 not extending- through the ])ase of the infected leaf into the next 

 leaves. If, however, the mycelium is found within the rootstock and 

 after a dormant period during midwinter follows the new shoots 

 upward in earh' spring and again ])roduces sori at the surface of the 

 plant, the rust is a true perennial. This condition appears to exist in 

 the following species. 



^CIDIUM TUBERCIILATUIM E. AND K. 



It is now usually supposed that all an^dial forms will likely be found 

 to he connected with other stages, though there are pro>)ably more of 

 these forms whose connections are at present undetermined than there 

 are of Lepto-uredinea\ If any ^Ecidium is more likely than another 

 to be an independent species, certainly the probabilities are largely in 

 favor of this species, which occurs on CaUirrhoe iiwolucr<(t<(,^' for there 

 is no need of another stage to perpetuate it, though another host 

 might give it a wider distribution. 



The striking orange-yellow color, large and otherwise conspicuous 

 sori, and its complete attack of every portion of the host make this an 

 unusually unique and attractive species (PI. I, frontispiece). A note con- 

 cerning the hardiness of this species was published by the writer sev- 

 eral years ago.'" The words are here quoted: '^JEc'xUnm tuberculatum 



«Bot. Gaz., Vol. XVIII, pp. -155-456. 



«< Though not previously reported, this rust was found also on CallirrliiH' filciruldes 

 at Sal in a, Kans., in May, 1893. 

 'Bot. Gaz., Vol. XVIII, p. 453. 



