The Scottish A aiuranst. 79 



Professor Miiller of Geneva is, however, the only one of the more 

 modern Lichenologists who utterly repudiates their use, and on 

 more than one occasion he has written to me in no measured 

 language of his abhorrence of such means of discriminating species. 

 In order to obviate the necessity for their use he is in the habit 

 (latterly at least) of giving such refined distinctions as are implied 

 in comparisons of length, breadth, size, colour, hardness, smooth- 

 ness, &c, &c, that the reader is confused and ultimately perplexed 

 instead of enlightened as to what he means — nay, so minute and 

 elaborate have his diagnoses become that they can only apply, in 

 their entirety, to individual specimens. As it is, the subject of 

 Lichenology (certainly the most difficult of the divisions of 

 botanical science) is fast becoming clouded instead of elucidated 

 by writers, each of whom is pursuing his pet line of investigation 

 independently of, and often in direct opposition to, his contempo- 

 raries. A state of matters which, by the way, is not without a 

 parallel in other sections of botany, and kindred branches of pure 

 science. When all this is to end is beyond me. Sooner or later, 

 however, a reaction must take place, One way out of the maze 

 would be to hold a conference of botanists, or better still, to sub- 

 mit all the known or alleged species and varieties of one genus, 

 seriatim to all who have written on it or described species under 

 it, and afterwards to compare results. In the interests of botany 

 I, for one, would gladly hail any such proposal. 



HETEKCEOISM IN TEE UREDINES. 

 By J. W. H. TRAIL. 



OF late years much has been written, and many observations 

 and experiments have been made, by Continental botanists 

 with a view of, in some measure, throwing light on the uncertainty 

 that still enshrouds the reproduction and the cycle of develop- 

 ment of this group of Fungi. The problem is one of no slight 

 practical value, relating as it does to some of the most wide-spread 

 and hurtful parasites of farm produce; yet despite its great 

 economic importance, and despite the almost universal diffusion 

 of these Fungi, there are few problems in the range of Botany 

 that have been more keenly debated, or that have found more 

 strenuous defenders for both sides of the question in dispute. 



It is doubtless known to most of our readers that there has 

 long been a suspicion that the " rusts " on the cereals are only one 

 stage in the life-history of the parasites, and that during a part of 

 their existence they live on other plants under a somewhat differ- 



