Double Fertilization in a Dicotyledon— 
Caltha palustris \ 
BY 
ETHEL N. THOMAS. 
With Plate XXX. 
T HIS striking and hitherto unknown phenomenon of double 
fertilization was, I think, first discussed in England after 
the publication of Professor Leon Guignard’s paper on Lilium 
Martagon and L. Pyrenaicum in the spring of 1899 2 . In 
August of the preceding year, however, Professor S. Nawaschin 
had given an account of his new researches on L. Martagon 
and Fritillaria tenella before the Russian Scientific Congress 
held at Kief 3 . 
It will be remembered that upon the expulsion of the 
contents of the pollen-tube into the embryo-sac of any typical 
Angiosperm, one of the two generative nuclei fuses with the 
nucleus of the oosphere, but the other has never been satis¬ 
factorily accounted for, and it was presumed that it became 
disorganized as the synergids do. Nawaschin, however, found 
in the plants mentioned that this second generative nucleus 
1 E. N. Thomas , 1 On the presence of vermiform nuclei in a Dicotyledon.’ Note, 
Annals of Bot., June, 1900. 
2 M. L. Guignard, ‘ Sur les anthdrozoides et la double copulation sexuelle chez 
les vegetaux angiospermes.’ Comptes rendus, t. cxxviii, Avril, 1899. 
s S. Nawaschin, ‘ Resultate einer Revision der Befruchtungsvorgange bei Lilium 
Martagon und Fritillaria tenella .’ Bull, de l’Acad. des Sc. de St. Petersbourg, 1898, 
novembre. 
[Annals of Botany, Vol. XIV. No. LV. September, 1900.] 
