308 ON THE GER^MIXATIOX OF CHAKA. 



veloped, and that their origin is invariably in the nodes or joints of the 

 roots, without occupying a constant position in relation to other parts. 

 Accessory leaves are unknown to me, unless indeed they may be said 

 to be present in the fruit-bearing parts of the Tolypellas, whereas 

 adventitious ramifications of all kinds occur as roots, fertile stems, and 

 accessory pro-embryos ; and, what is more, they may appear in the 

 nodes and joints of both similar and dissimilar members or parts. 

 Wahlstedt* has published some detailed observations on the appear- 

 ance of such shoots in many species, and their signification in the life- 

 history of the plant. Here we shall limit ourselves on this point to 

 a few remarks relative to the germinating plant. 



The production of adventitious roots from the peripheral cells of 

 nodes of the stem underground is a familiar fact. Hence the irre- 

 gular loots from the first two nodes of the germinating plant of Chara 

 may not improperly be regarded as accessory. 



All branches having their origin in the primary stem may be 

 termed accessory. Their appearance on leaves is unknown, though 

 probable ; but they are found springing from other nodes, and from 

 the base of the root. From the beginning their structure is analogous 

 to that of the fertile stems, with this exception, that in the corticated 

 species the bark is not formed, or imperfectly formed, on their lowest 

 internodes, whence Pringsheim's *' bare-footed " branches. 



Finally, accessory pro-embryos, which in structure, 'development, 

 and the lateral production of shoots are exact counterparts of the prin- 

 cipal pro-embryo, originate from tube-like outgrowths of the peripheral 

 cells as well of the nodes of the stem as the root, and also of the first 

 node of the plantlet. 



Those springing from the nodes of the stem have, since Pring- 

 sheim's researches, been known as branch pro-embryos. Accessory pro- 

 embryos on the root-joints appear in many species, at least, regularly 

 and often profusely. Wahlstedt points them out more particularly in 

 Lychnothamnm Wdlrothii and Chara aspera. The familiar white 

 spherical bulblets found on the underground parts of the latter plant 

 belong in all cases probably to the root. Each of these bulblets con- 

 sists mainly of a simple cell, well filled with an amylaceous substance, 

 and is in reality, in the cases investigated, nothing more than the 

 lowest relatively short swollen joint of a lateral rootlet. While 

 the swelling is still small a root-joint may be recognised at its apex 

 (the part farthest from the point of origin), which separates it from a 

 second joint of the same root, and which sends forth additional slender 

 lateral rootlets. When it has assumed its final shape and becomes 

 filled with starch, the upper root-joint sits upon it in the form of an 

 irregular body of several small cells, from which minute rootlets 

 radiate. Mostly these bulblets are clustered from 1 to 4 together on 

 the root-joints. They are also found on the nodes of underground 

 branches, but, so far as my observations go, always on the bare-footed 

 accessory branches. In this situation they exliibit the same structure, 

 and notably the same small-celled body with radiating thread-like 

 rootlets on their crown or apex. Hence here also, so far as our obser- 

 vations go, they belong to the root, representing its first joint. The 



* Om Characeernas Knoppar och ofvervintring. Lund, 1864. 



