Doyle — Observations on the Morphology of Larix leptolepis. 323 



The detailed ingrowth of the endosperm is the one feature still to be 

 determined. 



On June 2nd the archegonia were still in the same condition, but by 

 June 9th other activity began. The vacuolated archegonium follows the 

 usual course in becoming densely granular and compact. In the meantime, 

 the ventral canal cell is cut off, and henceforth appears as a shrivelled mass 

 at the top of the archegonium. The female nucleus becomes much larger 

 and stands centrally in the cytoplasm. Neither pollen tube nor any stage 

 of it was found in the ovules of this date. 



On June 15th in every cut ovule which had been earlier pollinated, 

 fertilization had been effected. The tube, which is very short, runs perfectly 



Fig. 5. — Larix leptolepis. Longitudinal section of mature ovule at fertilization 

 to show pollen germinating on nucellus b. a, integument, the micropylar 

 chamber still visible, e, endosperm, x 40. 



straight to the archegonium neck, so that if it appeared at all in the section 

 it appeared as a complete linear channel in the nucellus. It would seem, 

 then, that the time of actual growth of the pollen tube itself must be very 

 short, though this point cannot be sustained till the results from further 

 possible collections are available. The contents of the tube are emptied into 

 the archegonium, and the next stage observed was the very large fusion nucleus 

 still central, with three nuclei very close together in the upper part- 

 presumably the non-functioning male, the tube and stalk cell (Text-fig. 5.) 

 The closed over, upper micropylar chamber is shown. Unfortunately the 

 division of the body cell and the two male nuclei were not seen, so that it 

 cannot be decided whether Larix has the typically Abietinean inequality of 

 the male nuclei or not. Nor can Strasburger's (24) statement be verified 



