4 MARGARET C. FERGUSON 



reproduction in plants. Although the researches of Hofmeis- 

 ter, Strasburger, Warming, Belajeff and others who have con- 

 tributed to our knowledge of this subject, especially during the 

 last decade, have disclosed many facts concerning the structure 

 and development of the pollen-grain, of the ovule and of the 

 embryo, our knowledge of certain phases of spermatogenesis 

 and oogenesis is still very meager, and not a sufficiently large 

 number of plants have been thoroughly investigated to admit of 

 generalizations. The celebrated discoveries of Hirase, Ikeno 

 and Webber, in 1897, gave a new incentive to this study, par- 

 ticularly in connection with the Gymnosperms, and rendered it 

 highly desirable that fertilization and associated phenomena 

 should be worked out for other members of this group by the 

 more modern methods of investigation. 



The present studies were begun in the fall of 1897 with 

 the hope of adding somewhat to our knowledge of this subject. 

 Incidentally, it seemed desirable to determine whether any ves- 

 tiges of the bodies called blepharoplasts by Webber (i897 3 ) still 

 persist in the conifers. As a result of the past embryological 

 studies, a vast number of facts pertaining to the life-history of 

 the gametophytes in the higher platns has accumulated. While 

 many of the conclusions reached are the outcome of serious 

 direct investigations, others are based on the insufficient evi- 

 dence found in a rather superficial study of a large number of 

 plants. What we need to-day is not more facts regarding un- 

 related plants, so much as a careful working out of .the details 

 of development in representative genera. 



This research is based primarily upon a study of Pinus 

 Strobus, but nearly every observation recorded has been con- 

 firmed for Pinus rigida and P. austriaca^ and to a large extent, 

 for P. montana var. uncinata and P. resmosa. The descrip- 

 tions given may be understood to refer alike to the five species 

 named above unless otherwise stated in the text. Nearly six 

 hundred paraffin blocks with imbedded material have been 

 made, and more than four thousand slides of serial sections 

 have been stained and studied. Six hundred separate collec- 

 tions of material would seem unnecessarily large if one were 

 studying a plant like Nicotiana in which, according to Guig- 



