628 SUMMAKY OF CCTRRENT RESEARCHES RELATING TO 



pletely permeated by mycelium. On its surface are black irregular sclero- 

 tia, and otbers in a younger softer condition. When once attacked by the 

 disease, the plant inevitably perishes. The peziza-form will develope from 

 the sclerotia in the course of the next spring. This very closely resembles 

 P. TrifoUorum ; but inasmuch as the author found it impossible to infect 

 clover with sclerotia from the hyacinth, or the reverse, he proposes for it 

 the distinctive name Peziza hulhorum. In addition to Hyacinthus orientalis, 

 it occurs also in species of Scilla, and very rarely in Crocus. 



Germ-filaments produced from the spores in water produce sporidia, and 

 then perish, without infecting the host ; and, although it is quite possible 

 to produce an infective mycelium from spores, the ordinary mode of 

 infection is by the sclerotia only, the peziza-cups being comparatively rare 

 in nature. It is very easy to produce mycelium artificially from the 

 sclerotia, by removing the cortex or placing them in a nutrient solution ; 

 in the former case a fresh cortex is rapidly formed. By means of secondary 

 sclerotia, produced from the primary ones, the parasite is able to maintain 

 itself throughout an entire year almost without nutriment; and these 

 secondary sclerotia are the chief agents in the infection. 



Fluorescence of Fungus Pigment.* — According to Dr. A. Weiss, the 

 alcoholic extracts of fungi are all more or less fluorescent. The fluorescing 

 cone appears either green (yellow or brown fungi) or blue (red or violet 

 fungi) ; but the ochre-yellow pigment of some Agaricineaj fluoresced an 

 intense azure, the red pigment of the pileus of Amanita muscaria green. 

 The spectrum of the blue fluorescing pigment of Bussula and other fungi 

 showed a broad black absorption-band in the yellow-green, a thin one 

 between E and F, a total absorption of the violet to G. The band in the 

 yellow-green coincides with the band which the spectrum of a living red 

 peony leaf shows there, and likewise with that of the blue pigment of 

 many species of Campanula after treatment with sulphuric acid. The more 

 intense the colour of the extract, the more the absorption extends towards the 

 red ; so that with very thick layers of fluid the whole green and yellow seem 

 extinguished. The absorptions in the violet are similar to those of the red, 

 blue, and violet pigments of flowering plants. The green fluorescing 

 fungus-pigments show a faint absorption-band between E and F, and a broad 

 absorption of the violet end of the spectrum. 



Pathogenic Fungi-f — Mr. J. C. Arthur continues his reports to the 

 New York Agricultural Experimental Station. That for 1885 is devoted 

 chiefly to the study of plant diseases. The following topics are mentioned 

 amongst others : — 



Spotting of Quince Fruit. — This is due to a fungus, Morihiera Mespili 

 Fckl. var. Cydonise G. & E., always present to some extent on the leaves of 

 the quince. On the fruit it forms circular blackish spots with a red or 

 white margin and a dot or two at the centre. 



Hotting of Tomatoes. — The disease, or diseases, causing the rotting of 

 green fruit, and the early decay of the ripe fruit of tomatoes, seems as 

 difficult a problem to solve after another year's observation and experiment 

 as ever. A fungus, Macrosporum Solani E. & M., appeared in great 

 quantities this year ; it is often accompanied by a simple-spored fungus, 

 Phyllosticta Solani E. & M., which may indeed be but a later condition 

 of it. 



Lettuce Bust. — This disease, due to a fungus, Septoria Lactucse Pass., has 



* SB. K. Akad. Wiss. Wien, xci. (1885) pp. 446-7. 



t Rep. of Botanist to N. York Agricultural Experimeutal Stat., Geneva, N.Y., for 

 1885, Albany, 1886. 



