414 PROCEEDINGS OF THE ACADEMY OF 



December 2. 

 The President, Dr. Ruschenberger, in the chair. 

 Seventeen members present. 



Fertilization of Yucca Mr. Thomas Meehan detailed at length 

 the discoveries of Dr. Ensfelmann and Prof, llilev in regard to the 

 fertilization of the Yucca by the aid of a small niglit moth, 

 Pronuha yuccasella of Rile}^, and observed that in this region the 

 fertilization was effected by this insect ever^- 3'ear. In the Rocky 

 Mountains of Colorado in 1871, he saw the Yucca angustifolia, 

 everywhere seeding in great abundance ; but in his journe}' in 1873, 

 he saw not a solitary seed-vessel in any of the plants, and he sug- 

 gested that perhaps some periodical insect might take the place 

 of the Pronuba in that country. 



Note on a Fungoid Boot Parasite Mr. Thomas Meehan ex- 

 hibited a small Norway spruce, in which the branches and leaves 

 were all of a golden tint. He explained that when plants had 

 little food, or lost their fibres in wet soil by which they could not 

 make use of food, the yellow tint was generally exhibited in the 

 leaves of plants. The similarity of the appearances suggesting, 

 he examined and found the roots thickly enveloped by the my- 

 celia of a fungus, which destro^'ed the j'oung fibres as fast as they 

 were developed. Only a few trees had been attacked two years 

 ago ; but last season and this the fungus had spread underground 

 from one plant to another, till now there were over a hundred 

 in the diseased condition of the one exhibited. He had supposed 

 it was one of the small microscopic forms of fungi; but in Oc- 

 tober of the present year, the mycelia developed into a brown agaric 

 with a pileus about two inches broad, but the exact species of which 

 he could not positively determine. The mycelia of some of the 

 larger fungi would destroy the roots of grasses, as in the well- 

 known case of "fairj' rings;" and he believed the Gardener''s 

 Chronicle had conclusively shown that trees were also injuriously 

 affected by some of them ; but he thought that it had not before 

 been so directly proved in the case of American trees. 



He suggested, that, as the phenomena in the case of the trouble- 

 some disease known to American cultivators as the peach "yellows'" 

 wei'e all similar, those who had the opportunity to examine might 

 find the roots affected by a fungus in the same way. 



