PLASMODIOPHORA. 529 



The above-named investigators found plasmodia in various stages 

 of development in the palisade cells, and later in the spongy 

 parenchyma of diseased leaves. On treatment with " eau de 

 javelle " the plasmodia remained visible, whereas the contents 

 of healthy cells disappeared. Spore-formation has not as yet 

 been observed. The same parasite has been seen in vines in 

 the Ehine district. 



Eecently Debray and Brive^ have, in consequence of their 

 researches on Brunissure, removed the fungus from the genus 

 Plasmodiophora, and founded for it a new group Pseudocom.mis, 

 with a position near Vampyrella and Myxomycetes. This same 

 fungus they also found in a large number of plants from thirty 

 different natural orders. 



Plasmodiophora califomica Viala et Sauv.^ is another vine 

 parasite which causes greater damage than the preceding species. 

 Eeddish leaf-spots are produced, and extend so rapidly that the 

 leaves may drop early in spring. The parasite also affects the 

 shoots to such a degree that an abnormal number of shortened 

 branches are developed, the wood of which exhibits brown 

 stripes in autumn. 



It has not as yet been quite proved that the plasma observed 

 in withered vine leaves really consists of plasmodia of the 

 above two species of Plasmodiophora, nor have spores been 

 found. The true cause of the diseases has probably still to be 

 explained. 



In cases of root-deformation in pear, Miiller-Thurgau* observed 

 a slime-fungus in cells of the root-parenchyma. 



Tetramyxa. 



Spores united four together as tetrads and enclosed in a 

 delicate membrane. 



Tetramyxa parasitica Goeb.* First found by Goebel in 

 ditches of marshy meadows, causing tuberous balls of a whitish- 

 green to brown colour on leaves, flowers, and stalks of Ruppia 

 rostellata. Sections of the swellings showed the parenchyma 

 to be divisible into a dark brown central part consisting of 



^Compt. rendu., oxx., 1895; and " La Brunissure," Bevue de Viticvlture, 1895. 

 ^Oompt. rend., cxv., 1892, p. 67. 

 ■' Jahresiericht d. Vers. -Stat. W&denfweil, ii. 

 * Goebel, Flora, 1884. Identified in Scotland by Prof . Trail. 



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