Biologie. — Morphologie, Teratologie, Befruchtung, Cytologie. 211 
pen vorher durch Belichtung und die mit dieser verbundenen Tem¬ 
peratur bis zu einem bestimmten Grad vorbereitet, ausgereift sind.” 
Von besonderem Interesse erscheint, dass sich die Blüten ganz un¬ 
glaublich schnell — manchmal in 1 Minute — öffnen. 
Cuscuta europaea und lupuliformis fand Verf. auf einer grossen 
Zahl von Nährpflanzen schmarotzend, die den verschiedensten Pflan¬ 
zenfamilien angehören. O. Damm. 
Ewert, R., Die Parthenocarpie der Stachelbeere. (Vor¬ 
läufige Mitteilung.) (Ber. d. deutsch, bot. Ges. XXVIa. 1908.) 
Verf. fand an einem geknickten Zweig eines gegen Insekten¬ 
besuch geschützen Stachelbeerbäumchens, dessen Blüten alle kastriert 
worden waren vor dem Aufbrechen, eine parthenocarpische Frucht. 
Die Stauung der Assimilationsprodukte, hervorgerufen durch 
die wie ein Ringelschnitt wirkende Knickung des Zweiges hatte zur 
Entwicklung dieser Jungfernfrucht geführt. E. kommt zu dem Schluss, 
dass der Einfluss der Befruchtung auf die Fruchtbildung durch eine 
Korrektur der Ernährungsvorgänge ersetzt worden kann. 
Höstermann (Dahlem,. 
Fletcher, J. J., Illustrations of Polycot}Tedony in the Genus 
Persoonia [N. O. Pvoteaceae\. (Linn. Soc. N. S. Wales, Abstr. Proc. 
Nov. 25^. 1908. p. IV.) 
In 1882, as the result of his examination of the fruits of 23 out 
of a total of 61 described species of Persoonia , the late Baron von 
Mueller was able to announce that the embryos of 19 of them 
were polycotyledonous. The object of the present paper is to Sup¬ 
plement the Baron’s observations in so far as these relate to the 
species of Persoonia to be found in the neighbourhood of Sydney 
and on the Blue Mountains, from a study of seedlings, and 
whenever it rvas possible, of a considerable number of them. The 
cotyledons of about 700 seedlings, representing ten species, four of 
which are not in the Baron’s list, and in addition, the embryos of 
two species of which seedlings Tvere not procurable, one of which 
is not in the Baron’s list, were examined. The only seedlings or 
embryos with two cotyledons met with, were those of P. ferrnginea 
Sm. Not only is the number of cotyledons in all the other species 
examined inconstant, but about ten per cent. of the total number of 
seedlings were found to possess one, occasionally two, or rarely 
three notched, bifid, or bipartite cotyledonary members; some of 
these possibly may have been cases of connate cotyledons. As in 
all the other Proteaceous genera, two cotyledons are the normal 
number; and in view of the possibility, suggested by the discovery 
of two cotyledons in the Mesozoic Cycadophyte, Bennettites , “that 
the dicotylous condition was a primitive feature of the majority, if 
not all, Spermophyta,” *) the conclusion seems inevitable that poly- 
cotyledony in Persoonia represents a departure from the normal — 
that it is an acquired and not a primitive character; and that it has 
been derived from a dicotyledonous ancestor by the Splitting of the 
two seed-leaves. Author’s notice. 
1 ) Newell Arber and Parkin, "The Origin of Angiosperms.” Journ. Linn. Soc. 
Botany, XXXVIII, p. 73, 1907. 
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