.^ 



108 



DB. A. GBAY Olf THE STBUCTUBE 



Smithsonian Institution for leave to make the present use of the 



wood-cuts- 



Pig. 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 a ^^k- ^• 



Fig. 2. 



Fig. 3. 



Fig. 4. 



Fig, 6 



Fig. 6. 



Fig. 7 



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



' ^ I- ^ ^ 



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 ; 6, 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 *'^^' ^' 



4 h « ^ 



* * ^ 



a 



b 

 c 



hand 



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Fig. 1 1 



'^^ ^-^i ^-m 



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mn 



■the parts lettered as in fig. 9, viz 



i;, - 



^ X 



J X ri ^ 



I . * 



I r 



f", -* I * \ 



h n 



1^ - 



- '/■' 



J 



1 ■_■!- - 







^' ' 



_ J ^' _ 



^ « 



-^ ,T H. 



_■> J -- 



I_^ ^ 



■ + ^*M ,^t 



■- .^j-^-j-V- 



rt s— 



,-.... 



^.^.H-. H 



'^ J 



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