24 Transactions of the Society. 



the uninucleate nature of the typical vegetative cell has remained 

 one of the most firmly established of botanical beliefs. From time 

 to time cases have been brought to light indicating that it is not of 

 universal application, but such cases have until recently been 

 regarded, even by the observers who drew attention to them, as- 

 mere exceptions proving the rule, and Nageli's position has thus^ 

 remained almost unchallenged. But when we discuss modern 

 developments in the later part of this paper, it will be recognized 

 that in young tissues the occurrence of a binucleate or multinu- 

 cleate phase is too common to be dismissed as a mere exception,, 

 but must be treated as a normal, and possibly almost universal, 

 phase in the life of the plant. 



We propose here to give a brief sketch of the work of those- 

 observers who, since the time of Nageli, have recorded the occur- 

 rence of more than one nucleus in the vegetative cells of the. 

 higher plants. We shall entirely omit from this survey, the litera- 

 ture dealing with those recognized exceptions to the uninucleate 

 rule to which Nageli was the first to refer ; these exceptions have 

 chiefly been observed in connexion with reproductive structure&> 

 such as endosperms, tapetal cells, etc., and hence have no direct 

 bearing on our notions concerning ordinary vegetative tissues. We 

 shall also omit any account of cases among the Thallophyta, and 

 of pathological examples. 



Disregarding certain early references to binucleate cells, which 

 are probably mere errors due to indifferent optical appliances and 

 a rather vague conception of the nucleus, we find that the earliest 

 record of the occurrence of more than one nucleus in the purely- 

 vegetative cells of a Phanerogam is due to Schmitz (1879), who 

 observed this phenomenon in the older parenchyma cells of Glyceria 

 aquatica, Taraxacum officinale, etc. He had examined the Algte 

 widely from this point of view, and his notes on Angiosperms were 

 merely a side issue, but he prophesied that further work would 

 reveal the presence of multinucleate cells in a larger number of 

 the higher plants. He also placed on record the observation of 

 another worker in the same laboratory (E. Schmidt), that numerous 

 nuclei occurred in the tubular latex cells of Euphorhia. 



The next year Treub (1880) published independent observations 

 on the same subject. He states that the large cells of the paren- 

 chyma of Cereus rmtltiangularis were in several cases seen to 

 contain two nuclei, and the same thing was noted in Tradescantict 

 hypoplisea. In the pith of Ochrosia coccinea long cells occur, 

 the walls of which eventually become considerably thickened. In 

 these cells, when young, Treub found constantly as many as five to 

 eight nuclei ; after the thickening of the walls was completed the 

 nuclei were no longer distinct.* A comparable multinucleate stage 

 was described many years later in the case of the woody cells of the 



• Pigott, E. M. (1915). 



