black: inflorescence and fruit of pyrus malus 547 



Plate 37 



1. Longitudinal section of a young flower, showing the sepals, petals, and stamens 

 elevated above the carpels which are embedded in the torus. The ovarian cavities are 

 indicated. 



2. Cross section of a young flower showing the five carpels and the ovarian cavity 

 in each formed by the infolding of the edges of the carpel. The small dense cells demark 

 the carpellary tissue from the tissue of the torus. The ten primary vascular strands 

 are found in the latter. 



Plate 38 



1. Longitudinal section of a young flower, showing the origin of the ovule. 



2. Median longitudinal section, showing the unused portion of the apex of the axis 

 of the flower with a developing carpel on either side of it. 



3. Longitudinal section, showing the anatropous ovule and the inner and outer 

 integuments. 



4. Cross section of a young fruit. The demarcation of the carpels is shown by the 

 outline of small vascular strands around each one. A slight indentation is present in 

 the common tissue between two carpels in which the ventral vascular strands lie em- 

 bedded. The dorsal strand of each carpel is also shown as well as the ten primary 

 strands demarking the pith and cortex regions. 



5. Cross section similar to FIGURE 4, but showing two ovules in each ovary. 



6. Cross section of fruit, showing the position of the parts above the torus. The 

 five styles are free. 



Plate 39 



1. Longitudinal section of a mature ovule, showing the integuments, nucellus and 

 embryo-sac. The obturator is the projection just below the ovule. 



2. Longitudinal section of a fruit approximately 3/8 inch in diameter. The great 

 increase in the torus is marked. The cortex contains fibro-vascular bundles, the pith 

 is free from them. 



3. Cross section of fruit, showing the union of the styles to the tissue of the torus. 



4. Longitudinal section of the fruit, showing the unused portion of the end of the 

 axis of the flower and the prolongation into the fruit of the pith tissue of the stem. 



5. Longitudinal section of young fruit, showing one ovule cut in position. The 

 obturator is prominent. 



Plate 40 



1. Longitudinal section of a young embryo in the micropylar end of the ovule. 

 The endosperm tissue is well developed. 



2. Longitudinal section of an older embryo than shown in figure i. The embryo 

 is elongated, straight, and shows a well-developed vascular system. The formation 

 of the seed coat is well advanced. 



