248 DUPLICATION OF GENERATIVE NUCLEI BY MEANS OF 
the embryosacs. Moreover the reduction-division of the pollenmother- 
cells occurs much earlier than that of the embryosackmothercells. It 
results from this, that the nuclei of the embryosacks cannot simulta- 
neously with those of the tetradnuclei, be influenced by the same phy- 
siological stimuli. If, therefore, these external influences act exclusive- 
ly or preeminently, directly after the homotype division of the male 
nuclei, it may be assumed, that almost exclusively or exclusively du- 
plication of male generative nuclei takes place, which makes, that, be- 
sides normal fertilisation, almost exclusively union between haploid egg- 
cells and duplicated male generative nuclet will occur. 
In this respect (Cf. also Chapter X) we can compare Hyacinthus 
orientalis with Oenothera. About the latter GEERTS (1909 p. 111) writes: 
, Wenn in den Pollenmutterzellen die Synapsis und die Reduktions- 
teilung stattfinden, werden die Samenknospen nur eben angelegt, wäh- 
rend die Pollenkörner fast ganz erwachsen sind, wenn die Embryo- 
sackmutterzellen in dieSynapsis und die Reduktionsteilung eintreten.” 
Even if tetraploid progeny were found, it would still be incorrect, 
to consider this as proof of the fertilisation of a diploid eggcell by a 
diploid spermnucleus or by two haploid spermnuclei, derived from one 
plurinuclear pollengrain. Then, in the presence of pollengrains with 4, 5 
or more haploid nuclei, the possibility of trispermatic, besides disperma- 
tic, fertilisation 1s not entirely excluded. . 
6. This brings us to the question what is known of fertilisation of an 
eggcell by more than one haploid nucleus in the case of higher plants? 
Preparations, in which the fusion of an eggnucleus with a diploid 
male nucleus or with more than one haploid nucleus, could be observed 
have, as yet, not been obtained by us and could not be obtained, be- 
cause we have not yet made preparations of the fertilisation stages, 
thinking it advisable not to sacrifice any flowers, which we could ex- 
pect to set seed, as the first thing to do was to obtain good seeds, in order 
to be able to study the cytology of the seedlings. 
In the litterature we found the following cases: 
NEMEC (1912) found among preparations of Gagea lutea, 2 spermnu- 
clei fusing with an eggnucleus. He was unable to settle whether these 
2 spermnuclei were derived from another pollentube, than those which 
fused with the endospermnucleus, or not. He saw that the endosperm 
was tetranuclear. He considers the possibility of dispermatic fertilisation 
being favored by external stimuli : „Ja es ist nicht ausgeschlossen, dass 
