APEX OF THE ROOT IN OSMUNDA AND TODEA. 
75 
On the Apex of the Root in Osmunda and 
Todea. 
By 
F. O. Bower, IB. A., 
Lecturer on Botany at the Normal School of Science, South Kensington. 
(From the Jodrell Laboratory, Royal Gardens, Kew.) 
With Plates VIII and IX. 
Introduction. 
The years 1845 and 1877 will always be memorable in the 
history of the study of apical meristems. In the former year 
Naegeli published in his work, c Die neuern Algensysteme,’ his 
investigations on the mode of growth of certain Algae, notably 
ofDictyota dichotoma, and introduced the term apical 
cell (Scheitelzelle) to distinguish that cell from which seg- 
ments are cut off in regular order and succession, these 
segments giving rise, by further growth and division, to all the 
mature tissues of the organ. In 1877 Sachs produced the first 
of that series of memoirs 1 which drew together and systema- 
tised the immense volume of independent results obtained by 
various investigators of meristems during the previous thirty 
years. It is true that Hofmeister ( ‘ Lehre von der Pflanzen- 
zelle/ 1867, p. 125, &c.) had attempted to draw from a com- 
parison of various meristematic tissues, some general conclu- 
sions as to the relations of cell divisions to growth, but these 
1 1. “Ueber die Anordnung der Zellen in jiingsten Pfianzentheilen,” ‘ Verb, 
der Phys. Med. Gesellscli. in Wurzburg, ’ Bd. xi, 1877. 
2. ‘Arbeiten des Bot. Inst, in Wurzburg, ’ Bd. ii, Heft i. 
3. ‘ Arbeiten des Bot. Inst, in Wurzburg, ’ Bd. ii, Heft ii. 
4. ‘ Yoriesungen iiber Pflanzenphysiologie,’ pp. 523 — 55 7. 
