HA RD WICKE ' S S CIE NCE- G O SSIP. 



i°5 



dition of things in other fungi, e.g. the spores of 

 Puccinia graminis within the seeds of corn (see 

 'Gardeners' Chronicle,' August 22, 1885)." 



The three sections at A, B, c (Fig. 69), show trans- 

 parent slices of the fruit of the barberry. The little 

 circles in the outer rind of flesh of each berry are 

 CEcidium cups, some full of spores. The seeds within 



Fig- 71-— Puccinia within the seed of oats. 



each berry also exhibit similar CEcidium cups. At the 

 top right-hand corner of c a dotted quadrangle will 

 be noticed. This quadrangle is further enlarged to 

 50 diameters at the bottom of the illustration. The 

 thickness of the flesh of the berry is shown between 

 D and E, and in this flesh are four CEcidium cups — 

 two empty, and two immersed and partly hidden in 



the flesh. Part of a seed is seen at F, g, and CEcidia 

 are shown at H, empty, and j, full of spores ; an 

 immersed cup, almost empty, is shown at K, and 

 mycelium, etc., at L. 



When the seeds both of corn and barberry are less 

 extensively diseased than in the examples here illus- 

 trated mycelium only can be seen, but this is easily 

 enough recognised by any one properly acquainted 

 with CEcidium and Puccinia. The mycelia of 

 CEcidium and of Puccinia appear to me to differ from 

 each other. 



All experiments are perfectly worthless unless it 

 can be proved with the utmost certainty, before the 

 experiments are commenced, that there is not a 

 scrap of mycelium or a single spore of CEcidium or 

 Puccinia on or in the plants to be experimented with. 



Since the connection of barberry blight and corn 

 mildew has been supposititiously established, several 

 other examples of a like nature have been brought 

 forward on worse evidence than in the case before us. 

 Some instances are supposed to be supported by what 

 is no evidence at all. The minor examples can very 

 easily be disposed of. The barberry and corn subject 

 has, however, taken deeper root, but I think it has 

 now been shown that the diseases of the two plants 

 are probably distinct, and that both diseases almost 

 invariably traverse the host plants from the roots to 

 cotyledons within the seeds. 



Many fungi bear more than one sort of fruit. It is 

 known that certain fungi bear different kinds of fruit, 

 because the different fruits can be readily seen on the 

 same supporting threads. Until this is seen in the 

 fungus of barberry blight and the fungus of corn 

 mildew, any connection between the two must be con- 

 sidered unproven or improbable. For instance, if any 

 botanist will cause an CEcidium-spore, as at Fig. 70 A, 

 to germinate on corn (these spores germinate with 

 great readiness), and produce from its mycelial thread 

 a Uredo-spore, as at B, the case will be proved, i.e. 

 if the said botanist can permanently preserve his 

 specimen on a microscopic slide, and send it to the 

 British Museum for all coiners to examine. 



A similar piece of work is very easy with other fungi. 

 It is reasonable, always expected, and is always done 

 if anything is to be proved. Why, then, has it never 

 been done with the fungus of corn mildew ? Simply 

 because it cannot be done ; and all the writings and 

 illustrations produced in favour of the, at present, 

 purely supposititious connection of the two fungi are 

 not worth the paper they are printed on. 



The actual mounted microscopic slides of Puccinia 



graminis within the seed of oats and CEcidium bcr- 



beridis within the seed of the barberry, together with 



the material from which the sections were made, have 



been given to the Department of Botany, British 



Museum, South Kensington, where they may be seen 



by any one. 



WORTHINGTON G. SMITH. 



From the " Gardener's Chronicle.'' 1 . 



