THE FEMALE GAMETOPHYTE 



95 



very heavy integument. They have ben noted, for example, in 

 Campanula, Jasminum, and Salvia (Guignard 12 ), and in almost 

 all the species of Compositae investigated. In Calendula lusi- 

 tanica Billings 100 reports a very conspicuous synergid hausto- 

 rium, the synergids developing into the micropyle and much 

 enlarging. Synergid haustoria have been reported in other 

 forms, which are probably outgrowths of the sac. The behavior 

 of the synergids of Trapella, as described by Oliver, 21 is re- 

 markable, after fertilization increasing much in size, and in 

 the mature seed forming a conspicuous tubercle-like body 

 (Fig. 32). 



It has been generally assumed that the polar nuclei fuse as 

 soon as formed, which is perhaps generally true. If the time 

 of fusion be related to the act of fertilization, however, it will 

 be found to vary from before pollination to long after fertiliza- 

 tion, and in some cases, already mentioned (Lemna, Gymnade- 

 nia, Balanophora, Anlennaria alpina), the polar nuclei seldom if 



F IG . 44. 4, Salix petiolaris, upper end of embryo-sac soon after fertilization : />, pollen- 

 tube ; s, synergic! ; the synergids, which are beaked and have the " filiform appara- 

 tus," have broken through the embryo-sac into the micropyle ; x 694. B, S. glau- 

 cophylla, synergids not disintegrating after the formation of the embryo; polar 

 nuclei have not fused ; x 694. After CHAMBERLAIN.*' 



ever fuse. In this connection it may be noted that there is no 

 antipodal polar nucleus in Limnocharis (Hall 109 ) and Helosis 

 (Chodat and Bernard 83 ). Fusion of the polar nuclei at any 

 time from before pollination, as in Eichhornia (Smith 53 ), to 

 the moment of sexual fusion, as in LiUum, may be regarded as 

 normal. Later fusion of the nuclei has been noted in the 



