120 



cells, the primordial utricle and the nucleus becoming yellow under 

 the iodine. 



Another observer, Dr. Schenk*, has lately noticed the occurrence 

 of starch in a state of solution in the epidermal cells of the stem, 

 leaves, and other parts of Ornithogalum nutans and Ornithogalum 

 lanceolatum. These cells were found to contain (besides nuclei) a 

 thick homogeneous fluid. Tincture of iodine coloured the fluid first 

 wine-red, then violet, and finally indigo-blue ; and the fluid at the 

 same time lost its homogeneous nature, and became finely granular 

 and flocculent. 



The above mentioned are all cases of phsenogamic plants. The 

 Fungi have hitherto been considered wholly devoid of starch, un- 

 less, perhaps, the case mentioned by Schachtf may be an excep- 

 tion. He states that he observed the mycelium of a small mould- 

 fungus become clear blue under the action of iodine. He could not, 

 however, ascertain whether the colour was in the membrane or in 

 the contents, and if the former, it is as likely that the colour (being 

 clear blue) arose from the presence of cellulose in a young condition, 

 as from starch J. 



Mohl, in his treatise on the vegetable cell, speaks of starch as 

 probably existing in all plants except the Fungi. A special interest, 

 therefore, attaches to any plant of the latter tribe, in which starch 

 can be shown to exist, and such a plant has lately come under my 

 observation. The fungus in question, which is interesting not only 



* Bot. Zeitung, July 17th, 1857. f Die Pflanzenzelle, p. 39. 



J In the ' Aunales des Sciences Naturelles,' 4th Series, vol. iii. p. 148, Nylan- 

 der mentions a blue colour being produced by iodine in the summits of the asci 

 of certain Sphceriee, which he attributes to the presence of lichenin. Gerhardt, 

 however, in his ' Lehrbuch der Organischen Chemie,' states that a pure solution 

 of lichenin is coloured yellowish by iodine. 



It is not easy to understand why the writers who speak of amorphous starch, 

 take no notice of the lichens. Irrespective of the fact that the membrane of the 

 asci of lichens is coloured blue by iodine, it is well known that the asci and para- 

 physes are often surrounded by a viscid substance which is coloured by iodine in 

 the same manner as starch, and which cannot well be anything else than starch 

 in an amorphous state. Schacht, indeed, calls the viscid substance " aufgequol- 

 lene Starke;" but this expression would be more applicable to the condition of 

 starch when subjected to the action of hot water or sulphuric acid, and seems 

 hardly consistent with his previous definition of the substance as a shapeless, 

 paste-like mass. (See Die Pflanzenzelle, pp. 148, 149.) 



