(4*8) 



synonym of that species until cultures can definitely determine its 

 relationship. The fact that there is in the Orient another species 

 of the genus Heyderia, which might harbor the telial stage there, 

 lends support to the above suggestion. 



Development of the Telial Stage 



The telial stage of a number of species, especially those producing 

 fusiform swellings on the branches, has long been known to be 

 perennial, but Plowright (1889) was the first to show by means of 

 cultures the nature of the early development of such a form. 

 He found in experimenting with G. clavariaeforme that the " aecidio- 

 spores require two years in which to perfect the development of 

 perennial teleutospore mycelium." Aeciospores were sown upon 

 a juniper on June 25, 1884; about two weeks later some of the 

 leaves turned yellow and during the autumn these fell off leaving 

 bare places on the branches. The juniper remained in this con- 

 dition until December, 1885, when the bare branches showed signs 

 of swelling, and the following spring, April, 1886, telia were pro- 

 duced. More recently, Heald (1907, '09) working with G. Juni- 

 peri-virginianae (G. macropus), the common cedar-apple in eastern 

 North America, has shown by careful observations that it most 

 likely develops in a similar manner. Heald found very young 

 cedar-apples about the size of radish seeds to be present on the 

 cedars in June some days before any mature aeciospores could be 

 detected and this led him to suspect that these young galls were 

 the result of infection from aeciospores of the previous season, 

 and since his observations showed that they did not bear spores 

 until the following spring it seemed most likely that this mycelium 

 must require nearly two years to develop a cedar-apple bearing 

 spores. Observations of the writer substantiate this view. 



It would seem, therefore, that whether the mycelium is perennial, 

 i. e., remains alive in the cedar and produces spores for several 

 successive seasons, or whether it dies after having produced a single 

 season's crop, that it may in either case be developing for two years 

 before bearing spores. Further investigations along this line 

 are necessary in order to determine what the nature of the develop- 

 ment of the mycelium in the different species really is. Biennial 

 maturation may be the rule in species which have the telia appearng 

 on the twigs or branches, causing hypertrophy, and also in those 

 where the telia develop special outgrowths or gall-like excrescences, 



