M. Pringsheim on the Pro-Embryos of the Charse. 325 



first normal shoot of the Chora formed at the base of the pro- 

 germinal apex. 



This proof of the occurrence of the progcrm in the Chara fills 

 a sensible gap in the developmental history of those plants. The 

 existence of leafless provisional structures, from which the twigs 

 shoot forth, supports the conception, derived from the history 

 of the formation of the parts, that the twigs of Chara are leafy 

 shoots, and places the relationship of the Chara to the Mosses 

 in the clearest light. 



To the form of the seminal filaments and of the rudiments of 

 the fruit, in which the Chara so strikingly approach the Mosses, 

 we may now add the similar mode of production of the leafy 

 twigs from buds originating on confervoid leafless progerms; 

 for the progerms of the Chara differ but little in their structure 

 from the confervoid progerms of the Mosses, as is proved by the 

 possible replacement of their few and defectively developed 

 nodes by simple cells elongated into the form of joints. And 

 although the more simple and throughout almost confervoid 

 structure of the plant in the Chara, as also the node-formation 

 of their progerms, by which these externally resemble the leafy 

 twigs, renders the recognition of the progerms and their distinc- 

 tion from the leafy twigs very difficult, still it is never possible 

 to confound the progerms with leafy twigs, and no transition of 

 a progerm into a leafy twig ever occurs ; so that the morpho- 

 logical separation of the leafless progerms and the leafy shoots 

 is just as sharply marked in the Chara as in the Mosses. 



Lastly, the complete morphological equivalence of the progerms 

 in Chara and Mosses shows itself most decidedly through the 

 progerms of the twigs in the former ; for, among all leafy plants, 

 it is only on the stems and leaves of the Mosses that we find 

 organs analogous to the progerms of the twigs of Chara. These 

 are the well-known root-like prothallia which occur on the stems 

 and leaves of many Mosses, and which have been fully described 

 by W. P. Schimper in his anatomical and morphological investi- 

 gations on the Mosses*. 



The Chara, therefore, in their general process of development 

 pass through similar stages to the Mosses. 



They are leafy plants, without a main stem or main root, the 

 whole of their twigs, like those of the Mosses, being produced 

 as lateral shoots, either on other leafy twigs or on leafless pro- 

 germs. 



* Compare the structures described by Schimper in his ' lleeherches 

 anatomiques et morphologiques sur les Mousses' (Stiasburg, 1848), as 

 "radicelles proembryonnaires sur les tiges" (p. 13), " excroissances pro- 

 embryonnaires sur le limbe et a l'extremite de la nervure des feuilles " 

 (p. 15), and "radicelles proembrvonnaires aux feuilles dctachces de la tige" 

 (p. 19). 



