M. Miillcr o/i the Development of Chara. 255 



organs can be no longer obtained, the substance being destroyed 

 by winter, and as at the next opportunity I may not have the 

 leisure for continuing these researches, I shall present here the 

 observations which I have collected. 



As regards the history of this family, we find in Kaulfuss's 

 paper* a complete sketch of it up to that time, to which I must 

 refer; subsequently, Bischofff, Schultz J andMeyen§ have made 

 valuable contributions. Kiitzing || has detailed some general 

 observations, and Fritzsche some beautiful investigations on the 

 anthers in his paper, " Ueber den Pollen ^^^, which however leave 

 several points open for future observations. Nageli has lately 

 written on the moving spiral fibres in the mucous threads of the 

 anthers**, and Mettenius on the same subject in the 'Bot. Zeit- 

 ung,' 1845. 



Considering the labours of these observers as known, I shall 

 confine myself strictly to my own investigations. But as we have 

 to commence the history of the development with the germ, I 

 do not consider it superfluous again to give a description of the 

 spore in that stage in which it has attained its greatest deve- 

 lopment (especially as it contains some new facts), because by a 

 knowledge of the organ, in which the formation of the new plant 

 occurs, our knowledge of the process itself must become more 

 perfect. 



§ 2. The Ripe Fruit. 



When divided through the axis it appears composed of three 

 distinct coverings : 1. an external one (the spore-sac) ; 2. a mid- 

 dle one (the sporular membrane) ; and 3. an internal one (the 

 nucleus) (Plate V. fig. 1). 



The spore-sac is a thick, more or less pyriform covering, upon 

 the apex of which five approximated thick cells are situated, 

 forming a kind of crown. This covering is formed of five cells, 

 which are spirally wound around the spores several times — usually 

 twice. The former five short cells form the summit of the spores. 

 Each of these cells when divided appears four-sided, their inner 

 surfaces being flattened towards the spores, the outer ones to- 

 wards the atmosphere, and the lateral ones towards each other. 

 The planes of the latter however are arranged in an undulatoiy 

 manner. These, like the former cells, are composed of three 

 distinct membranes ; an external one or epidermoidal mem- 



* Erfahrungeu iiber das Keimen der Charen, Leipzig, 1825. 



t Krypt. Gew. 1 Lief. 1828. 



X Natur d. lebendigen Pflanze, Bd. 2. p. 470. 



§ Physiologie, especially in the third volume. |I Phycolog, general. 



1[ Mem. do I'Acad. Imp. des Sc. de St. Petersbourg. 



** Ztschr. f. phys. 13ot. Bd. 1. Heft L p. 168. 



