i6 The Irish Naturalist. January, 1918. 



IRISH SOCIETIES. 



DUBLIN MICROSCOPICAL CLUB. 



November 14. — The Club met at Leinster House, the President (N. 

 CoLGAN, M.R.I. A.) in the chair. 



Prof. G. H. Carpenter showed a preparation of the male reproductive 

 organs of the Warble-fly {Hypoderma hovis) and a section through the 

 testes. In the latter some of the details of the spermatogenesis could 

 be distinguished, and chromatic cytoplasmic inclusions such as the 

 mitochondria were recognisable. 



D. M'Ardle exhibited Dicranella heteromalla, Schp. showing the pale 

 yellow seta and capsule with rostrate lid, peristome with large red teeth, 

 cleft to the middle into two or three divisions. He also showed the male 

 plants which are seldom seen, and were collected recently on the Dublin 

 Mountains at Killakee ; they are smaller and stouter, and their leaves 

 are less falcate, and form a terminal coma around the conspicuous oval 

 inflorescence. In this stage they may be passed over by the student 

 for a species of Pleuridium, and would require to be dissected for the 

 antheridia. A drawing of Pleuridium alternifolinm was shown for 

 comparison. This interesting silky-leaved moss is common in Ireland, 

 easily identified by the yellow seta when in fruit. 



H. A. Lafferty exhibited the oospores of a species of Phytophthora 

 parasitic on Tomato, Aster, Petunia and Wall-flower seedlings, the disease 

 being recognised by the falling over of attacked plants. Up to the present 

 the oospores have only been obtained in pure cultures and their method 

 of formation is identical with that described for Phytophthora erythroscptica, 

 the oogonium (female) entering the antheridium (male) at its base, growing 

 up through it, eventually bursting out at the top where it swells out 

 forming its oosphere and later its oospore. Pure culture studies and 

 infection trials have proved that the fungus is quite distinct from any 

 of the previously described species of Phytophthora. 



W. F. GuNN exhibited a slide of Tubifera ferruginosa, a species of 

 Mycetozoa. It was found in August last, in the plasmodium stage, on 

 a decaying fir-stump near Rathdrum, and was then of the less usual 

 yellow colour. The plasmodium is usually of a watery white colour, 

 but, in rare cases, bright yellow. As in some other genera of this group 

 of fungi the sporangia combine to form a sort of compound colony known 

 as an aethalium. The slide showed a vertical section, and clearly 

 exhibited the brown sporangia, with their iridescent walls and contained 

 spores, seated upon the white spongy hypothallus. 



