22 BRITISH CHAROPHYTA. 



memoir " Ueber die Vorkeime und die nackefiissigen 

 Zweige der Charen ' in ' Jahrb. wissens. Bot.' iii, with 

 its large series of beautiful illustrations, a few of which 

 are reproduced on Plate III. The subject has been 

 further investigated by the eminent Swedish botanists 

 Nbrdstedt and Wahlstedt, to whose writings,* as well 

 as to Pringsheim's and De Bary's memoirs, those 

 wishing to pursue the matter are referred. 



Pro-embryonic growths similar to those proceeding 

 from the oospore are also frequently produced at the 

 thickened lower stem-nodes of the sexual plants often 

 in considerable numbers. In Lamprothamnium papn- 

 losum (Lamprotliamnus alopecuroides Braun) a second 

 rhizoid-producing node, but similar in structure to the 

 double foot-like node of the root, is sometimes pro- 

 duced between the oospore and the pro- embryonic 

 root-node, as noticed by Wahlstedt and described and 

 figured by Miss M. McNicol, in ( Annals of Botany,* 

 xxi, p. 66, t. 8 (1907). 



An early sta'e in the development of 

 Sexual Plant. J 



the young shoot is shown in Jrl. Ill, t. 5. 



The apical-cell (a) which is approximately hemispherical 

 in form represents the growing point, and it is by a 

 succession of transverse divisions and the subdivision 

 of the parts cut off, that the whole of the plant is built 

 up. This process is shown in Fig. 3 (p. 23). In i. the 

 apical cell (a) is undivided ; in ii. by the growth of a 

 transverse septum it is divided into two cells (a and ft), 

 the former remaining at the growing point, the latter 

 becoming again divided by a second transverse septum, 

 as shown in iii. the upper portion (c) forming a 



* L. J. Wahlstedt, ' Om Characeernas knoppar ocli ofvervintring.* 

 (Lund 1864). C. F. O. Nordstedt, "Nagra iakttagelser ofver Characeernas 

 groning," in Lund's ' Univ. Arrskrift/ ii (1865-6 ). Nordstedt and Wahlstedt,. 

 "Ueber die Keimung der Characeen," in ' Flora/ Iviii, pp. 94-5 (1875). 



