36 FARLOW ON THE GYMNOSPORANGIA 



sporidia of G. glohosinn had become mixed with those of the two other species. Such 

 a supposition is possible in the case of G. macrojms which often grows in company with 

 G. cjlohos^im, but it can hardly be true of the G. hisejitatum in question, which grew in 

 a deej) swamp remote from G. rjJobosinn, and the s^jecimens of which were collected and 

 covered with care to prevent a mixing of the spores with those of other species. 



Whether we consider the distribution of our species or the results of the cultures made, 

 there is nothing to confirm the views of Oei'sted as to the connection of particular species. 

 In this connection, I would refer to a paper by Rathay known to me only by the abstract 

 given by Magnus in Bot. Zeit., 1880, p. 798. The method of culture adopted by Rathay is 

 unknown to me, but he came to the conclusion that R . penicillata belonged not as a form 

 of i?. laceraia to G. davariaeforme, but to G. fuscum. If then our G.fiiscum var. gloho- 

 stmi be really a variety of G. fitscwn, and if H. j^eniciUafa be a form of B. cancellafa as 

 supposed by Rathay, then the sjDermogonia on C. tomentosa, which so frequently followed 

 the sowing of the sporidia of G. globosiim, might be supposed to belong to what I have 

 called li. penicillata, which does occur on Crataegus in the United States. One could not 

 be at all certain, however, Avithout seeing the fully developed aecidia, but it must not be 

 forgotten that tho; e who are fully imbued with the belief that the different aecidial genera 

 as Aecidium, Roestelia, etc., are stages of Puccinia, Gymnosporangium, etc., accept the ap- 

 pearance of spermogonia alone, without having seen the aecidia, as strong proof of a con- 

 nection between different forms. In fact the instances where the aecidia themselves liave 

 been produced by cultures of teleutospore forms are very few in number. But even if we 

 admit that the spermogonia following the sowing of G. fuscum belonged to R. jicnictllata, 

 what are we to say of those which followed the sowing of G. mcicroinis and G. hisepta- 

 tura ? It is absolutely impossible to consider G. hiseptatum a form of G. fuscum, nor, in 

 my opinion, is there any reason to suppose that G. macrcjAts is a form of that species. 



Spermogonia followed sowings of G. maci-opus on both C. tomentosa and Amelanchier, 

 and accordingly they might have belonged to R. laceraia or R. aia^antiaca. R. cornuta 

 may be excluded as belonging, according to Oersted, to G. conicum, which is not in the 

 least related to G. macropus, and the distribution of R. hyal'ma makes it very improbable 

 that it is connected with the ubiquitous G. macropus. R. lacerata shoidd be connected 

 with G. davariaeforme and, as has already been remarked, Schroeter has suspected that 

 G. macrojius may be a form of the last named species, but I have already stated my rea- 

 sons on structural grounds for not considering them two forms of the same species, and I 

 do not think that that belief should be altered in consequence of the results of my cultures. 

 There remains then R. aurantiaca which might possibly be connected with G. macrojnts. 



The case of G. hisejjtcduvi is still more desperate. It certainly cannot be connected 

 with R. jienicillata, or R. lacerata, and if we assume it probable or even possible that 

 there is a connection between G. macropus and R. aurantiaca, there is only left R. cor- 

 nuta to be matched with G. bisejJtatiim, and this would imply that G. conicum and 

 G. hiseptaium were forms of the same species, which I presume that few botanists are 

 willing to admit, for excellent anatomical reasons. 



The reader has probably in the last few pages been surfeited with if's and or's, and a 

 choice of rather bewildering alternatives. There is only one more point to be suggested 

 in this connection. That is, that the appearance of the spermogonia after sowing the 



