230 



of fragmentation than with the just mentioned ovule. 



In an ovule, collected on September 19, the endosperm 

 is so strongly developed that of the nucellus-tissue hardly 

 anything remains visible. This also applies to the cases 

 which will be described presently. The endosperm-cells hâve 

 strongly thickened but still fairly gelatinous walls; the 

 contents of the cells consist of a number of small grains 

 which stained very strongly and which somehow make the 

 impression of nucleoli ; of a nucleus nothing is found any 

 longer, unless we apply the name to some thick, coloured 

 masses. 

 Three ovules, fixed on December 15, ail showed the same 

 picture (flg. 9). A strongly developed endosperm is présent 

 with very thick cell-walls, absorbing safranin more or less, 

 and protoplasts which are entirely foamy and in which 

 nothing of a finer structure is found. This endosperm must 

 evidently be reckoned among the horny ones ; it was extre- 

 mely dif&cult to eut. Sections of the ovules could only be 

 made after treament with hydrofluoric acid. It is not impos- 

 sible, of course, that the foamy appearance of the protoplasts 

 must be ascribed to this treatment, although we do not 

 think this probable on account of other expérience with 

 this method. In the endosperm some fissures are visible, 

 the last remuants of the cavity of the embryosac. 



Finally an ovule with an endosperm was found among 

 the material collected on January 19, Hère also cutting was 

 only possible after treatment with hydrofluoric acid. The 

 endosperm is entirely disorganised, borders of cells can 

 scarcely be recognised. No more than in the preceding cases 

 we think this must be ascril)ed to tht- manner of treatment. 



We hâve now described ail cases of formation of an 

 endosperm, observed by us. It will hâve been noticed that 

 the order is not chronological, the arrangement was such 

 that we gradually proceeded from the least developed to 

 the complète endosperm. From this it follows already that 



