2o6 



Introduction to Botany. 



identity of the parts of perigynous and epigynous flowers 

 their embryology must be called in evidence. It is seen 

 that the parts of a flower first arise as minute lobes of the 

 receptacle, as at a in the diagrams. In hypogynous 

 flowers the plane of insertion of the lobes remains nearly 

 the same throughout the development of the flower {a, b, 

 c, d, A). In perigynous flowers the outer zone of the 

 receptacle is soon found to extend upward so that the 

 insertion of the sepals, petals, and stamens is raised to a 



higher plane (a, b, c, d, B). 

 In epigynous flowers a 

 broader zone of the recep- 

 tacle grows upward, carry- 

 ing higher the planes of 

 insertion of all of the floral 

 parts {a, b, c, d, C). In pe- 

 rigynous flowers (B) the 

 hollow extension of the re- 

 ceptacle may vary greatly 

 in height, thickness, texture, 

 and color ; it may be thick 

 and cup-shaped, as in the cherry and plum (Fig. 124); 

 urn-shaped and contracted at the summit, as in the rose ; 

 thin and corolla-Hke, as in Solomon's seal and hyacinth, 

 where it is commonly called the perianth tube. In epigy- 

 nous flowers there may be a tubular extension of the 

 receptacle beyond the pistil, as in fuchsia (Fig. 123, D); 

 or an extension of the receptacle may form a solid shaft 

 surmounting the ovary, bearing sepals, petals, stamens, 

 and styles at its summit, as in Iris. But in this instance, 

 and in some others where the pistil is inferior, it may be 

 that the inner portion of the outer wall of the ovary is 

 carpellary tissue adherent to the hollow receptacle. 



Fig. 124. 



Longitudinal diagrams of the flowers of 

 (fl) rose, (^) plum, (c) Solomon's seal. 



