518 On a New Clover Disease. 



of these external filaments. They are larger and are repeatedly 

 branched. The mycelium shown in Fig. 1 appears to be simple 

 and formed of a single cell, whilst in the aerial portion it 

 is much branched and formed of many cells. This distinction 

 does not, however, always hold good ; for I have seen the myce- 

 lium branched, and composed of many cells. After frequent 

 searching, I have not been able to discover the reproductive 

 organs of this fungus. The portion growing on the surface of 

 the stem has been always barren. The rapid spreading of the 

 disease among isolated plants shows that the spores must be 

 abundantly produced, although I have failed to see them. With- 

 out the fruit I am unable to refer this parasite to its proper 

 genus. As its mode of growth agrees in many respects with the 

 potato fungus, it most likely belongs to the same genus (Per07io- 

 sporci), and may perhaps be the same species {P. ivfestans). 

 This supposition is the more probable, as last year a crop of 

 potatoes were grown quite near to the clover, which would 

 supply in abundance the spores that have attacked the clover. 

 But in the potato the spores of the fungus germinate on the 

 leaves, which are the first part attacked ; while it appears to me 

 that the leaves of the clover are unsuited to the parasite, the 

 spores of which germinate in the soil, and the mycelium attacks 

 the base of the stem. If this hypothesis is true — and it is the 

 more probable, because the further the clover was from the 

 locality of the potato it was the freer from disease, and it dis- 

 appeared altogether at 50 metres' distance (55 yards) — then 

 agriculturists should not grow these two crops near each other. 



In the ' Annales des Sciences Naturelles ' for 1863, M. de Bary 

 refers to a Peronospora, which he had frequently noticed on 

 clover, and on this account called P. trifolii. This inay be the 

 same as the fungus I have given an account of; but his short 

 description does not enable me to identify it. 



But though the origin and name of this parasite are obscure, 

 the disease exists none the less, and without the means of stop- 

 ping it. I will continue my obserAations, and, if you have 

 room, will submit the result of them to your readers. 



[The disease described above agrees very closely Avith that 

 which has attacked the bases of straw in our cereal crops in 

 some Avet seasons, and which I described at length, under the 

 name of " StraAV-blight," in the A^olume of this ' Journal ' for 

 1872. As the ergot attacks only the groAving ears of the different 

 grains on which it occurs, so these diseases on clover aiKl straAV 

 attack the same part of the plants, namely the first or second 

 internode. The reproductive organs haA^e not been detected in 

 either case, so that it is impossible as yet to determine the true 

 position of the fungi. The draAvings given and the arguments 



