lly NOMAD FUNGI. 



laughter, has now become an article of science ; and in a few years the 

 man who dares to question it will be received with as much ridicule 

 as were those who formerly believed it. The Norfolk farmers, and 

 others, always held that the presence of barberry bushes in the hedges 

 of their cornfields had something to do with the rust and mildew of 

 their crops ; and this belief, though doubtless founded upon rough 

 reasoning only, turns out to be quite correct. Many other beliefs of 

 country bumpkins, now held up to scorn as instances of superstition, 

 will in future years become a part of the scientific creed. 



A perfect Uredinous fungus has, then, three distinct stages — the 

 CEcidium, the Uredo, and the Puccinia, distinguished by Continental 

 mycologists as I., II., and III., as will be seen by referring to the table 

 of the revised classification on pages 112-8. The spores of these are 

 called, sometimes, protospores, stylospores, and teleutospores respec- 

 tively; but the number of species in which all the three stages have 

 been observed is comparatively few, and in the great majority either 

 two or only one stage is at present known. 



It must not be supposed, however, that a Uredine which has all 

 three stages need pass through them every year. Just as in Phanero- 

 gams, a plant may have several modes of multiplication, of any of 

 which it may avail itself according to circumstances. For instance, 

 Mr. Plowright has shown that Puccinia i)oaru)n is a stage of (IJcidiian 

 tua.-iiliifiiiiis ; yet the Puccinia has been hitherto unknown in Britain, 

 while the CEcidium occurs in vast abundance everywhere. A similar, 

 but reversed, instance occurred in another of his experiments, where 

 he produced (Ecidium zonule {a, plant new to the British flora) by 

 sowing the spores of Uromi/ces jiiiici. Even if we grant that the newly- 

 discovered fungi did e.Kist before in Britain, it must be in small 

 quantity and in few places only. So Peridcrmium pini is a stage of 

 C'oleosporiuin scnecionis : the latter is very common iniles away from any 

 locality where the former can be found. Stages II. and III., or their 

 phijxiolofiical equicalentii, must indeed occur in most cases ; but the 

 oecidium-stage need perhaps only occasionally intervene. Vide infra. 



In the genus Phragmidium the cecidium-stage has been hitherto 

 but little known (I might say, in England altogether unknown),* and 

 frequently confounded with the uredo-stage. In both cases the sori 

 are surrounded by a ring of paraphyses, but in the case of the CBcidium- 

 soi'us the spores are produced in chains ; in the uredo-sorus each spore 

 grows smgly. For Triphragmium no stage I. has yet been discovered,! 

 which is also the case with our species of Melampsora. In Melampsora 

 and Coleosporium, stage II. is the ordinary uredo-like form, in which 

 the spores occur in heaps like dust ; stage III. is that in which the spores 

 are closely compacted ; in Melampsora, 1 to 4-celled and with a 



* Mr. Plowright has recently recorded it in "Science Gossip" for January, 

 1883, pp. 11-12. 



t The uredo-stage has, however, two forms— the one appearing in spring, 

 physiologically, perhaps, but not morphologically representing the (Ecidium, 

 the other in summer being the true Uredo. 



