JoumoK — C7/r//sophl//ciis endohiotka and other Chytridincece . 141 



species the presence of two distinct mycelia-one giving small male organs 

 or antlieridia, the otlier, larger female receptive organs or oogonia. The 

 antheridium becomes connected by a narrow canal with the oogonium, and 

 fertilization occurs. The resting spore is thus an oosperm or zygote. Fischer 

 on the other hand, says in Urophlyctis there is no act of fertilization. The 

 resting spore is the terminal cell of a hypha which also forms, just below 

 it, an accessory or collecting, more or less swollen cell, which becomes less 

 conspicuous as the resting spore develops. Magnus's views on TJ. leproides 

 are based, he states liimself, on the spirit material he received. I have 

 not seen any illustration of the female mycelium he describes beyond the 

 indistinct structure he shows (op. cit., figs. 29 and 33, V. leproides) and calls 

 " the remains of the carrying threads [or mycelium] of the receptive cells." 

 In his paper on U. Eubsaameni Magnus considers 'as the remains of the 

 host-cells' tufts of short appendages described as protoplasmic threads or 

 appendage-threads by Schroeter and Biisgen. Tljeso occur often at the 

 same point on the convex side of the resting spore in U. Rubsaameni, as 

 his remains of the female mycelium iu JJ. leproides. If I am correct in 

 my observations that in TJ. leproides the host-cells become disintegrated as 

 the tumour enlarges, may not the U. leproides remains also be those of its 

 host-cells ? In the examination of the spirit-material of TJ. leproides at my 

 disposal, I have seen nothing to support the view of the sexual origin of the 

 resting spores in Uroplilyetis. 



Flax-Yellowing. 



The flax crop, almost wherever it is cultivated, is liable to be troubled 

 not only by the yellow rust Melampsora lini, but by a more serious form of 

 yellowing, called in Belgium le feu or la brulure, due to a member of the 

 Chytridiacese, Asterocystis radicis Wild., the life-history of which, so far as 

 it is known, was made out by E. Marchal (16) in 1892. I have received 

 flax-yellowing due to it for report from various parts of Ulster. The 

 disease appears in wet, low-lying parts of the field, and is indicated by the 

 premature yellowing of the seed- and other lower leaves of the young plant. 

 The stem loses its firmness, and its tip topples over towards the ground. The 

 roots have a peculiar glassy, flabby appearance, and are easily pulled out of 

 the ground. The parasite is confined to the roots, attacks the root-hairs and 

 the roots generally, leaving only the central cylinder untouched. Tims the 

 yellowing of the foliage is caused by the choking up and destruction of the 

 absorbing tissues of the roots, i.e., to starvation of the plant by the interference 

 of the parasite. This occurs as a plasmodium in the host-cells, and passes, iu 

 a way at present conjectured only, from cell to cell in the root, reproducing 

 itself by swarm-sporangia like those of other Chytridiacese. Tliese sprout 



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