Uredosporcs. 3 1 



trifolii, etc., the brown colour being due to the spore-wall. 

 The colouring matter of the uredo and aecidiospores has 

 been spectroscopically investigated by Bachmann.* He 

 examined the aecidiospores of Gyninosporangium jiiniperi- 

 num and Piiccinia coronata, and the uredosporcs of Me- 

 lanipsora farinosa, TripJiragmiiim nlma^'icE, and Uromyces 

 alchemillcB. Combined as it is with some oleaginous 

 material in granules, and enclosed within the cell walls 

 of the spores, it is exceedingly difficult to extract it with 

 ether. But by adopting the saponification process of 

 Kuhne t and Hansen % he was able to arrive at the follow- 

 ing conclusions. The above-named fungi give very similar 

 spectra, namely two narrow absorption bands, one between 

 b and F, the other between F and G, showing that the 

 pigment is the same in all cases ; that it is very similar to, 

 if not identical with, the colouring matter of most of the 

 yellow phanerogamous blossoms (the anthoxanthin of 

 Hansen) although combined differently, and allied to the 

 xanthophyll group. It is soluble in alcohol, ether, chloro- 

 form, bisulphide of carbon, and benzol, and is coloured 

 green by potassium iodide. 



As soon as the uredospore has arrived at its maturity 

 it becomes separated below from the hypha which produced 

 it (basidium, sterigma). This separation takes place by 

 the basidia breaking off eitlier close to the spore (Uredo) 

 or at a short distance below, in which case the upper part 

 of the basidium remains attached to the spore (Trichobasis). 

 This separation is facilitated, if not caused, by the spore 

 being pushed off by the continued formation of other 



* E. Bachmann, " Spektroskopische Untersuchungen von Pilzfarbstoffen " 

 (1886), pp. 21-23, figs- 27-31. 



t W. Kiihne, " Ueber lichtbestandige Farben der Netzhaut " (" Unter- 

 such. d. physiol. Inst. d. Univ. Heidelberg"), bd. i. hft. iv. p. 347. 



$ F. A. Hansen, «' Der Chlorophyll Farbstoff" (" Arbeitendes botan Inst, 

 zu Wiirzburg"), bd. iii. hft. i. p. 126. 



