and Fertilization in Oenothera. 283 
rotundifolia by Pace ( 51 ), and in Epilobiitm angustifolium by Modilewski 
( 42 ), whose figures are, however, not very clear. The writer has had an 
opportunity to observe it in the last-mentioned plant (Text-fig. VIII, 4) 
and also in Circaea quadrisulcata (Text-fig. VIII, 5), as well as in Godetia sp. 
(Text-fig. VIII, 1 a, 1 b), though 4 is not so good as 1 for illustration. 
The indentation which is associated with the filiform apparatus, though the 
reverse is not always the case, has been apt to be overlooked by many 
investigators, probably owing to the fact that its morphological or physio¬ 
logical significance is scarcely understood. 
The apical part of the synergids is occupied by the filiform apparatus, 
which is a solid mass of a conical shape, and is perforated by a number of 
minute canals which arise on the basal part and converge towards the apex, 
as fully described by Habermann ( 25 ). As its development had not been 
faithfully followed, it was quite impossible to fully make out the plexus of 
immense canals. Only in some cross-sections stained with gentian violet, 
quite a number of minute pores were clearly made out, which must be the 
cut ends of the canals. 11, 12Text-fig. I, are intended to show an 
external appearance of these canals. The following has been compiled to 
supplement Habermann’s list of the plants in which the filiform apparatus 
is found : Actaea spicata , Podophyllum peltatum described by Huss ( 30 ), 
Helianthus annuus illustrated by Nawaschin ( 46 ), Gcircinia Kydia, 
G. Treubii figured by Treub ( 71 ), Parnassia palustris , Saxifraga ligulata , 
S. Sponheimica , 5 . cordifolia , Pleuchera broxoides, Drosera rotundifolia , 
Atmosco texana , and Gyrostachys gracilis described by Pace ( 51 , 51 <2, and 
52 ), Myricaria germanica by Fristendahl ( 18 ), Butomus iimbellatus by 
Holmgren ( 29 ), Trifolium pratense by Martin ( 40 ), Myosurus minimus by 
Tchernoyarow ( 70 ), Ottelia lancifolia by Palm (53 a), and finally Godetia 
sp., Gaura Lindheimeri , G. parviflora , Epilobium angustifolium, and 
Ludzvigia prostrata observed by the present writer, as shown in Text-fig. 
VIII, 1 a, 1 b, 2, 3, 4, 11. In the mature sac of Oenothera and some other 
plants examined, all belonging to the Onagraceae, a large vacuole usually 
appears below the nucleus in each of the synergids, which is clearly figured 
in Text-figs. I, 11, 12, vac., and VIII. 
The pole nucleus ( p.n .), which is almost in contact with the oosphere, 
increases markedly in size, and is provided with a large nucleolus. As a rule, 
in the eight-nucleate embryo sac, the secondary embryo sac nucleus is very 
voluminous, owing, of course, to the fusion of the two polars; but in the 
case of Oenothera the single polar without any additional nucleus acquires 
a conspicuously large volume. This fact suggests that the polar shares the 
nutritive function, acting as the antipodals, though the chromatic condition 
of the nucleus is too normal for the one in such an active condition. 
In the nucleolus of the polar, one or several vacuoles are always 
present, which are often replaced by a crystalline structure, and the same is 
