Origin of Spore-forms. 37 



is no essential point of distinction between aecidiosporcs and uredospores, 

 for though the former are always formed in chains, yet undoubted uredo- 

 spores may also be thus produced. Hence there is no valid distinction 

 between the two, even to the matter of nuclei, for both are binucleate. 



The aecidiospore is just like the uredospore, thin-walled, and adapted 

 for immediate germination; but since it is essentially a spring form, and 

 required to keep pace with the rapid growth which then takes place, it is 

 not formed solitary upon a stalk, but tier upon tier, to make abundant 

 provision for the coming season. It is usually uredospores and aecidio- 

 spores which are confounded together, but there is one case at least in 

 which the aecidiospore partakes of the character of a teleutospore. In 

 Endophyllum the spores are produced in chains, and within a pseudo- 

 peridium just like normal aecidia, but instead of germinating in the usual 

 way, each one produces a four-celled pTomycelium, giving rise to promy- 

 celial spores just like a teleutospore. They may either be described as 

 aecidiospores which produce promycelia or as teleutospores resembling aeci- 

 diospores. This genus is not now generally regarded as independent, but 

 as related biologically to Uromyces or Puccinia, and it will probably turn 

 out to be a case where an aecidiospore still retains marks of its earl} origin 

 from a teleutospore in its mode of germination, (Note 4, p. 75.) 



SPERMOGONIA AND SPERMATIA. 



If the aecidiospores were the ^result of a sexual process, as is some- 

 times maintained, then of course they could not be derived from teleuto- 

 spores, and the mere fact that I have attempted to account for their origin 

 from this source shows that some other explanation must be forthcoming 

 for the so-called male sexual organs spermogonia and spermatia. In 

 lichen-fungi such as a Collema a true process of conjugation occurs, and 

 the male organ or spermogonium, with its contained spermatia, resembles 

 very closely in structure the similarly named bodies in the rusts. It was 

 Tulasne who originally discovered these bodies in 1851, and who suggested 

 their sexual nature, which he based partly on the fact that the spermatia 

 were not known then to germinate, and partly that they usually preceded 

 or accompanied the bodies they were supposed to fertilize, viz., the aecidia. 



Great attention has, therefore, been paid to the spermatia, in order to 

 discover if they were capable of germination, and it has been found that 

 in a nutritive solution they grow and bud after the manner of yeast, but 

 no definite mycelium has been produced. 



It is generally stated that the spermogonia either precede or accompany 

 the aecidia, but they may occur with all the spore forms, according to the one 

 which is first produced. Aecidia usually follow the germination of the 

 sporidiola, and therefore spermogonia accompany them most frequently : but 

 if the first formed spore is the uredo, as in Tripliragmium uhuariae, Uromy- 

 cladium maritimum, and Puccinia obtegens (Lk.) Tul., then they accompany 

 it, and if a teleutospore as in P. liliacearum, Duby. or Uromycladimn tep~ 

 perianum, the spermogonia are associated with it. But Arthur 3 states the 

 case more generally when he remarks that " every one who has made cultures 

 of the rusts knows that in about a week after sowing the germinating teleu- 

 tospores there will appear spermogonia, without any regard to the kind of 

 spore that is it'o follow." There are even instances where the spermogonium 

 has entirely disappeared, as in Puccinia malvacearum, Mont. It is ac- 

 knowledged by those who have given special attention to the subject that 

 the spermogonium is an isolated organ, of uncertain origin and function, 

 and that the balance of evidence is against its being a sexual organ. The 

 spermogonium is seldom absent from the life-cycle, and vet it takes no direct 



