1 1 2 Blackman and Welsford. — - Fertilization in Li lium. 
This led to a close examination of the material, and later similar 
material was obtained of Lilium auratum ; and material of Petunia violaceae 
was also collected for comparative observations of a Dicotyledon. As this 
work has been interrupted before completion it seemed worth while to publish 
figures and a brief description of the results obtained in Lilium ; for it 
is a surprising fact that while L. Martagon was one of the first forms 
in which triple fusion was observed, yet there exist no really satisfactory 
figures even of the more obvious details of fertilization of that form. 
Guignard’s well-known illustrations, though sufficient for demonstration, are 
only text- figures and leave much to be desired. 
One of the points which our figures bring out clearly is the complete 
absence of male cells even at the stage in which the nuclei have only just 
left the pollen-tube (PL XII, Fig. 5). In fact Nawaschin 1 has recently shown 
that the cytoplasm of the generative cell is lost in the general cytoplasm of 
the pollen-tube at the time that its nucleus gives origin to the male nuclei. 
In all cases the male nucleus fusing with the polar nuclei is somewhat 
larger and more contorted than that which fuses with the female nucleus. 
The figures here published show more clearly than earlier ones the form 
and structure of the male nuclei of Lilium. When the male nuclei have 
just entered the embryo-sac, but are still surrounded by the contents of the 
pollen-tube (Fig. 5), the vermiform character is very apparent, and the 
chromatin, though not of an ordinary resting type, yet shows a network. 2 
At a later stage (Figs. 1 and 6) the chromatin stains more deeply and 
begins to be arranged in threads. Later on (Figs. la, lb, a,c) the chromatin 
threads are very thick and distinct. Nawaschin associates these signs 
of activity in the chromatin with the self-motility of the male nuclei, but it 
is possible that it is a mere preliminary to fusion or to the subsequent 
division of the fusion-nucleus, for, as Fig. 4 shows, the chromatin of the 
female nucleus sometimes becomes thread-like immediately before fusion. 
Our studies of these two species of Lilium have led us to the view, 
held by Nawaschin for the forms he has studied, that the male nuclei have 
the power of movement, and by their own activity make their way to the 
nuclei with which they fuse. The shape of the nuclei, understandable 
if the nuclei have to push or writhe their way through cytoplasm, would 
seem quite unsuitable to their carriage by strands of cytoplasm. We have 
further been able to make out that in many cases the polar male nucleus is 
distinctly more pointed at one end, and sometimes this difference between 
the ends is very marked (Figs. 2 a, zb, 2 c ), though it has not been possible 
1 Nawaschin, S. : Naheres liber die Bildung der Spermakerne bei Liliiwi Martagon. Annales 
du Jard. Botan. de Buitenzorg, 2 e ser., Suppl. iii, 1910, 871-904. 
2 In this our observations do not agree with those of Nawaschin (1910, loc. cit.), who states that in 
Z. Martagon the male nuclei do not pass into the resting state, but the chromatin retains the arrange- 
ment characteristic of the telophase of the last division. His observations appear, however, to be 
based on studies of the pollen-tube outside the embryo-sac. 
