112 



sed. Its tip after penetrating into 

 the large embryosac has become 

 distended, probably due to endos- 

 mosis. X 50. 



Fig. 34. Embryosac isolated and subse- 

 quently cut in halves. One half X 100 

 The prothalliumcells (y) are mono- 

 nucleated. The pollentube (blue) has 

 penetrated into the embryosac (red). 

 Among the free nuclei of the fertil 

 part a large male generative nucleus 

 is seen at «. The prothallium is kept 

 black. 



Fig. 35. Showing degeneration of cells 

 at the top of the nucellus prepara- 



tory to the formation of a pollen- 

 chamber. X 1200. 

 Fig. 36. Embryosac, allready fertilised, 

 X 100. The large embryosac is drawn 

 red, the nuclei and protoplasm of 

 the fertil part red also. The pollen- 

 tube which has penetrated, blue, 

 it contains besides protoplasm and 

 some starch but the poUennucleus; 

 the generative nuclei not visible in 

 this section. At the top are four 

 reduced embryosacs (black) the two 

 larger ones left and right to the 

 median line,thetwosmallerin theme- 

 dian line. Prothallium drawn in black. 



PLATE VI, 



Fig. 37. The top part (A) of fig. 36. X 600. 



Fig. 38. The top of the prothallium (B) 

 of fig. 36, X 600. 



Fig. 39. The top part (A.) of fig. 36. 

 X 250, after dissolving of the 

 contents by means of chloral 

 hydrate and staining with »Bis- 

 marckbraun". The colors here and 



in the other figures are diagramatic. 

 Fig. 40, Longitudinal section of part of 

 the nucellus, showing pollentube pe- 

 netrating into the embryosac. X 50. 



P. := Pollentube. 



R. E. = Reduced Embryosac. 



F, :zr Fertil part of embryosac, 



S. = Steril part of embryosac. 



PLATE VII, 



Fig. 41. Pollentube just burst after 

 having penetrated the embryosac. 

 X510. 



The two larger nuclei are the ge- 

 nerative ones, the small one is the 

 pollen nucleus. 

 Fig. 42. Part of Embryosac, immedia- 

 tely after fertilisation. X 510. 



P. N. rz PoUennucleus. 



H. z= Hole in the wall of the 

 pollentube through which the gene- 

 rative nuclei have escaped. 



C. P. = Copulationproducts of one 

 generative nucleus and one nucleus 

 of the fertil part each. 



The oter nuclei are nuclei of the 

 fertil part of the embryosac. 

 Fig. 43. Another case like fig. 42. x 510, 



Letters as in fig, 42, 

 Fig. 44. Next step in the development. 

 X510. 



P, =. Pollentube. 



P. N. z=z PoUennucleus. 



W, 0, E. z= Wall of Embryosac, ad- 

 pressed to it two free nuclei of the 

 fertil part of the embryosac, 



Z. = Zygotes. 



The other cells are retarded pro- 

 thallial cells of the fertil part of the 

 embryosac. 

 Fig. 45. Embryosac into which two pol- 

 lentubes have entered. X 250. Stai- 

 ned with methylen green -f lo/o acetic 

 acid and after washing out, with 

 gentian violet. 



