558 THE AMERICAN NATURALIST. (VoL. XXXIX. 
tops of young flowers that several species of Taraxacum pro- 
duced normal seeds apogamously and concluded that the embryo 
must develop parthenogenetically since Schwere, in 1896, traced 
its origin from the egg. Ostenfeld (:04a, : 04b) from failure to 
find pollen on the stigma of Hieracium and failure to make it 
germinate in a number of solutions, was led to try similar experi- 
ments to those of Raunkiaer in cutting off the anthers and stig- 
mas of flowers. He found that a large number of species of 
Hieracium were able to set seed apogamously and he believed 
parthenogenetically but histological investigations were not made 
to establish the last point. The experiments of Raunkiaer and 
Ostenfeld are interesting as showing how a form by virtue of its 
parthenogenetic habits might become segregated and quite re- 
moved from the probability of hybridization. Murbeck (: 04) in 
a short paper announced that the embryos in Taraxacum and 
Hieracium, developing from flowers whose stamens were cut out 
(as in the experiments of Raunkiaer and Ostenfeld) actually do 
develop from the egg cell and are therefore parthenogenetic. 
Murbeck also failed to find pollen tubes in the ovules where 
pollen had been applied to the stigma. Winkler (104) reports 
that Wikstremia indica matures very little perfect pollen and 
produces its seeds apogamously, as proved by experiment. The 
embryos are stated to develop parthenogenetically from the egg 
but no details are given in this preliminary paper of the chromo- 
some history. This group of contributions while very interest- 
ing, presents no data on the fundamental problems in a cyto- 
logical explanation of parthenogenesis. 
Murbeck (:01a) concluded for Alchemilla that true tetrads 
were formed previous to the differentiation of the embryo-sac 
but nevertheless found evidence that there were no reduction 
phenomena so that the nuclei within the embryo-sac contain the 
sporophytic number of chromosomes. Murbeck’s evidence of 
tetrad formation was not satisfactory and in the light of recent 
studies of Strasburger (:04c) cannot be accepted. His view 
was, however, correct that there is no reduction of the chromo- 
somes in the formation of such embryo-sacs as produced par- 
thenogenetic embryos. 
Juel (:00) gives a critical comparison of the development of 
