PERENNIAL SPECIES. 27 



incubation period is shorter if inoculating material is taken from liv- 

 ing plants, and during the summer it is probably about the same as 

 that of infections from uredospores. 



Numerous experiments were also made with other lepto species, 

 including Puccinia grindelise, Pk. , P. variolans, Hark. , P. lygodesmiae, 

 E. and E., and P. shercirdiana, Korn, with results similar to those 

 above mentioned. The writer has already called attention to the 

 phenomenon of the formation of eatenulate sporidiola in two of these 

 species, P. grindelive and P. variolans. 



PERENNIAL SPECIES. 



The chance for the continued existence of a rust through winter 

 resistance of the uredo without the intervention of another stage has 

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

 nial host, or at least one that lives over winter, it must 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 base 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 early spring and again produces sori at the surface of the 

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

 the following species. 



iEciDIUM TUBERCULATUM E. AND K. 



It is now usually supposed that all recidial forms will likely be found 

 to be connected with other stages, though there are probably more of 

 these forms whose connections are at present undetermined than there 

 are of Lepto-uredinese. If any iEcidium is more likely than another 

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

 favor of this species, which occurs on Callirrhoe involucrataf 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: "^Ecidium tuberculatum 



«Bot. Gaz., Vol. XVIII, pp. 455-456. 



& Though not previously reported, this rust was found also on Callirrhoe alcxoides 

 at Salina, Kans., in May, 1893. 

 cBot. Gaz., Vol. XVIII, p. 453. 



