108 



DR. A, GEAT ON THE STEUCTUEE 



Smithsonian Institution for leave to make the present use of the 

 wood-cuts. 



Fig. 1 represents a magnified vertical section of a pistil 

 of Magnolia umbrella^ from a flower-bud about thirty 

 days before anthesis ; showing one of the forming ovules, 

 the other being cut away. The ovule at this time is an 

 apparently homogeneous cellular protuberance. Fig. 2 

 represents the ovule a week or two later in a similar 

 side-view : the two coats now appear as rings or shallow 

 and thickened cups around the base of the nucleus. 

 Fig. 3 is another ovule, as it appeared a few days later. 

 Fig. 4, another a few days later. Fig. 5, one from 



Fig. 8. 



Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. 



nearly full-grown flower-bud. Fig. 6, one from a just- 

 opened blossom. Fig. 7, a vertical section of the same 

 through the middle of the raphe. Fig. 8, a transverse 

 section of the same. In both these sections the conspi- 

 cuous cord of vessels of the raphe is shown to occupy a 

 position about midway between the outer and inner surface of 

 the primine, or external coat ; and this continues to be its po- 

 sition throughout the growth of the seed. 

 Fig. 9 is an outline section of a full-grown 

 ovule, like fig. 7, but on a larger scale, so that 

 the parts may be lettered and compared with 

 the figures beneath : a, is the primine or outer 

 coat ; 5, the inner coat ; c, the nucleus. Fig. 

 10 represents a slice of the tissue from the left- 

 hand side of fig. 9, through the raphe and 

 primine combined, the inner coat and a little 

 of the nucleus ; and fig. 11, a corresponding 



Fig. 9. 



Fig. 10. Fig. 11. 



slice from the right-hand side,— the parts lettered as in fig. 9, viz. 

 a, the outer coat ; J, the inner coat ; c, a portion of the tissue of 



