Aug. 18, 1870] 
phenomenon of Alternation of Generation among Fungi. | 
The researches of Steenstrup and others have made us 
familiar with this remarkable phenomenon among the 
lower forms of animal life, but had hardly prepared us to 
meet with it in the vegetable kingdom. 
bable, however, that the phenomenon is by no means 
uncommon here also,—affording another instance of the 
law that it is in their lowest forms that the animal and 
vegetable kingdoms approach one another most nearly,— 
and that whole tribes of fungi hitherto considered distinct 
are but different phases of one another. This remark 
applies especially to the two genera of minute parasitic 
fungi, 2ctdium and Puccinia, to which the rusts in ques- 
tion belong, both belonging tothe family Uredinee. The 
well-known orange-red spots so common on the leaves of 
the berberry are produced by the £cidium berberidis, 
while the rust of wheat and other cereal crops, but found 
equally on some other species of grass, as the common 
couch-grass or Triticum repens, is the Puccinia gramints. 
In the volume for 1865 of the MWonatsberichte der kin. 
eos Akademie der Wissenschaften zu Berlin is a paper 
y Dr. De Bary, giving an elaborate account of his ex- 
NATURE 
It appears pro- | 
319 
periments on the propagation of these two fungi, in which, 
if his experiments are reliable, he clearly proves the correct- 
ness of Sir Joseph Banks’s suggestion that they are one 
| andthe same species. The experiment was tried, with due 
precautions, of inoculating the leaves of the berberry with 
the spores of the Puccinza, the result being the produc- 
tion, not of the same fungus, but of the cédium, while 
the sowing of the spores of this latter fungus on the leaves 
of couch or wheat produced conversely the Puccinia. By 
sowing the spores of either fungus on the plant on which it 
was itself parasitic, he failed altogether to reproduce 
the same plant; and this alternation of generation may 
serve to account for the fact which has often been noticed, 
that rust is apt to appear not in successive but in alternate 
years on the same crop. 
It is unfortunate to find that in a work bearing a 
considerable amount of scientific authority among agri- 
culturists, and published in the same year, 1865, Prof. 
Buckman’s “ Science and Practice of Farm-cultivation,’ 
the theory which thus appears to have been proved-on the 
Continent was scouted in the following terms: “A£cidium 
berberidis is here referred to, from an opinion prevailing 
Fic. B.—£cidium berberidis, Gmel. 1. 
of Peridia with their orifices dentated. 
Branch of berberry 
that it is the cause of rust or mildew in wheat. We can 
no more believe that the berberry rust would produce rust 
in wheat than the rust of any other plant would do so. 
Still that wheat growing under a berberry hedge may be 
more blighted than in the rest of the field is quite true, 
and so it is with wheat growing under any kind of hedge.” 
Mr. Buckman fails entirely to grasp the argument, which 
is not that wheat “growing under a berberry hedge” is 
attacked by rust, but when growing in the proximity of a 
berberry tree, say at the distance of a field’s breadth. 
Nothing is more certain to weaken the hold of science 
over practical men than when men of science, in order to 
support their own theories, set themselves systematically 
to deny well-known facts. We therefore greatly regret 
the decision at which it is understood the council of our 
Royal Agricultural Society has arrived, to refuse a 
thorough investigation of the subject which has been 
urged upon them, calling in the assistance of experienced 
men and the most able fungologists of the day. This is 
not the way to command the confidence of practical 
farmers. 
We commend to the consideration of the Royal Agri- 
cultural Society the conduct-of a railway company in the 
south of France, described in the Axdletin de la Société 
botanigue de France for January of this year, to which 
with spots of rust, natural size. 2. Spermagonia, 
3. A group 
4. Sporidia, (2, 3, and 4 magnified.) 
we have already alluded (see NATURE, vol. i., p. 516). 
In the commune of Genlis, department of Céte-d’-Or, a 
berberry hedge was not long since planted on one of the 
railway embankments ; when immediately the crops of 
wheat, rye, and barley in the neighbourhood became 
infested with rust. The complaints of the farmers caused 
the appointment by the company of a commission to 
investigate the subject, who reported, after a full inquiry, 
that wherever the berberry was planted the cereals were 
more or less attacked by rust ; where they were absent 
the crops were free from the disease ; and that the planting 
of a single berberry bush was sufficient to produce the 
rust where it had never appeared before. The railway 
company’s own commission held that compensation was 
due from the company to the farmers. 
Our illustration of the &£cidium berberidis is taken (in 
part) from Greville’s “ Scotch Cryptogamic Flora ;” that of 
the Puccenia graminis from Corda’s “ Icones Fungorum.” 
ALFRED W. BENNETT 
In considering the question of the influence of the 
berberry on the production of rust in wheat, assuming that 
De Bary’s observations are perfectly correct, it is neces- 
sary to consider the nature of what is commonly called 
“yust” in cereals, Presuming that his views are strongly 
