FLORAL DEVELOPMENT OF HELIANTHU8 ANNUUS. 123 



the ovule, as, were it lateral upon the axis, and having regard to its 

 direction of growth, which is always towards the centre, we should 

 hardly expect to find it so inclined, but rather that its point of 

 origin was nearer to the outer carpellary leaf, leaving a space for the 

 rudimentary or suppressed axis. The terminal character of the 

 ovule receives further support from the consideration of its after 

 development, which points to the nucleus being the termination of 

 the floral axis, the other point concerning which doubt exists ; those 

 who regard the ovule as lateral, and consequently as a modified leaf, 

 considering it a new formation on its superior surface. 



Growth of the funiculus from the first proceeds unequally, most 

 rapidly on that side which is towards the circumference of the 

 capitulum, the result being that its base speedily becomes horizontal, 

 and that that point which was originally axial in position, and 

 which seems to me to be the true floral axis, is by degrees forced 

 over, and is found as a slight projection on the inner side below the 

 summit. Figures 11 to 13 represent this at various periods of its 

 progress. 



When the funiculus has attained the height of -^-^ of an inch, 

 the first indication of the integument is seen as a ridge across its 

 summit (Fig. 14), which, growing forward, forms a hood-like pro- 

 jection over the now apparent nucleus, for the original apex has 

 begun to grow faster than hitherto, and to keep pace with but 

 slightly in advance of the integument. It has also altered in 

 appearance and character, being clear and transparent, the cells 

 being most distinctly nucleated. The young nucleus at first stands 

 at right angles to the funiculus, but during development it is 

 gradually depressed through an angle of 90°, and thus attaining its 

 anatropal character (Figs. 15, 16). At length its further develop- 

 ment is retarded, and it becomes covered by the integument, or 

 primine, the ovule having but one envelope. 



Now having regard to the facts as above stated — first, that the 

 earliest indication of the ovule is a rising of the floor of the ovary, 

 with a bluntly projecting centre ; second, that growth proceeds 

 more rapidly on the exterior side of the funiculus, by which the 

 blunt point of the centre is gradually forced over, though never lost, 

 that the nucleus is developed at this point at the same time, or just 

 after the primine — it seems to me we cannot regard the ovule as 

 other than a terminal structure, and the nucleus as the apex of the 

 floral axis. 



Turning now to the question as to the presence or absence of a 



