2 Transactions of the Society. 



rated many case's in which these phenomena had been observed, 

 but we did not describe them individually. In the present instal- 

 ment I propose to deal with the history of the vegetative nucleus, 

 so far as this history bears upon the binucleate phase, in the 

 following species, each of which has been chosen as presenting 

 certain features of interest : — 



1. Eremurus himalaicus Baker (PL I, figs. 1-11, and pp. 2-6). 



2. Asparagus officmalis L. (PI. I, figs. 13, 27, 28, and pp. 6-11). 



3. Helianthus Nuttallii Torr. et Gray (PL I, figs. 21-24, and 

 pp. 11-12). 



4. Helianthus tuber osus L. (pp. 12-13). 



5. Syringa vulgaris L. (p. 13). 



6. Monstera deliciosa Liebm. (PL I, figs, 39 A and B, and p. 14). 



7. Hemerocallis fulva L. (PL I, figs. 33-37, and pp. 14-15), 

 Nothoscordum fragrans Kunth (p. 15), and Alisma Plantago L. 

 (PL I, fig. 38, and p. 15). 



8. Polygonum cuspidatum Sieb, et Zucc. (PL I, figs. 25 and 26, 

 and pp. 15-16). 



9. Morus nigra L. (PL I, figs. 12 A-C, and pp. 16-18). 



10. Hippuris vulgaris L. (PL I, figs. 17-20, and pp. 18-19), 

 and Modea canadensis Michx (PL I, figs. 29-32, and p. 19). 



11. Stratiotes aloides L. (Text-figs. 1 and 2, and pp. 19-21). 



1. Eremurus himalaicus Baker (PL 1, figs. 1-11). 



Eremurus himalaicus is a large and vigorous member of the 

 Liliace?e, which throws up in the spring a rapidly -growing raceme 

 of numerous flowers, sometimes attaining the height of 6 feet or 

 more by the middle of June. The developing inflorescence axis 

 affords very favourable material for the study of the binucleate 

 phase. A transverse section of the axis in the flowering region 

 reveals a broad vascular zone enclosing a small central pith, 

 the whole surrounded by a narrow parenchymatous cortex. Such 

 a section, examined while the inflorescence is quite immature 

 (e.g. in the latter part of April), shows that the great majority of 

 the cells of the pith and the ground tissue between the bundles 

 contain two nuclei, or in some cases as many as three. Binucleate 

 cells also occur, though more rarely, in the cortex, which consists 

 of elements of smaller diameter than tliose of the pith and ground 

 tissue. The epidermis appears to be entirely uninucleate. A 

 study of the origin of the supernumerary nuclei shows that they 

 invariably arise by mitosis. The cells contain vacuolate cyto- 

 plasm. When a nucleus is about to divide the cytoplasm appears 

 to be attracted towards it, and it becomes suspended from the 

 lining layer by more numerous, conspicuous and well-defined 

 bridles than in the case of those nuclei which are in a condition 



