57 



1. Those of the female spikes are fertil aM consist of a 

 nucleus surrounded by 3 envelops. 



2. Those of the male spikes are steril and contain a 

 nucleus with but two envelops; the failing envelop 

 is the middle one. In the nucleus no embryosac develops. 



The female flowers are secondary axes or buds, the nucellus 

 is the top of the secondary axis. 



3. The integuments surrounding the ovule of Gnetum 

 do'nt belong to the ovule, while the inner integu- 

 ment develop after the outer one. 



The three envelops of the ovule are nothing but three ap- 

 pendicular whirls each arising from the concrescence of two 

 appendices. 



The external whirl is the perigonal one. 



The middle whirl corresponds to the staminal whirl of Wel- 

 witschia. 



The third is the pistil (II terro e il sacco pistillare che io 

 chiamo nucellaria). 



The central nucleus is the naked nucellus , the tip of the axis. 

 In 1879^) Strasburger again took up the study of the develop- 

 ment of Gnetum Gnemon. 



About the source and condition of the material at his dispo- 

 sal he says: 



„Das Material bekam ich in zwei Sendungen durch die Giite 

 des Herrn Dr. R. H. C. C. Scheffer aus Buitenzorg auf Java. 

 Es sollte zu embryologischen Untersuchungen dienen und ent- 

 hielt anscheinend alle Entwickelungszustande von der Bliithe 

 an bis zur reifen Frucht. Leider wareu in beiden Sammlungen 

 die Samen ohne Keimanlagen. Die Bestaubung war ausgeblie- 

 ben und ungeachtet viele Samen sich anscheinend normal wel- 

 ter entwickelt hatten , so war doch ihr Embryosack entweder 

 vollig obliterirt oder fiihrte doch nur Endosperm. Zu embryo- 

 logischen Untersuchungen war also das Material nicht zu brau- 



1) Stkasburger. Die Augiospermen und die Gymnospermen. Jena 1879, p. 100. 



