308 



PHYLUM XIV. ANTHOPHYTA 



Fig. 184. — Prunus. 



are borne on the margin of the cup, and here are found the 

 five round, pinkish petals, and the five, green-pointed 

 sepals. As the seeds mature the tissue of the cup enlarges 

 and softens into the flesh of the ripe apple, while the five 

 carpels constitute the "core." Thus in the apple as in 

 the strawberry the fleshy, edible tissue belongs to the 

 flower-axis, and not to the proper fruit (the core). 

 In fact we eat the cup (flower axis) and throw the fruit 

 (core) away! 



565. In the Plum (Prunus) the cup has become deeper 

 and narrower than in the Spiraea, while the carpels are 



reduced to only one with 2 ovules. 

 The stamens are still many, 20 or 

 more in whorls of 5 or 10 each, on the 

 margin of the cup, while the petals 

 and sepals are as in Spiraea. The 

 (free) carpel in ripening softens and thickens its outer 

 tissues into an edible flesh, while the inner tissues imme- 

 diately surrounding the seed are hardened into a stone 

 (sclerenchyma). 



566. The Pea flower (Pisum) has a shallow cup, and in 

 its center a single monocarpellary pistil, as in the Plum 

 flower. Here, however, instead of two ovules there are 

 several, so that the pistil becomes elongated. 

 The stamens on the margin of the cup have 

 been reduced to ten, and nine of these have 

 grown together by their filaments, leaving 

 one free. The five white petals are unlike, 

 so that the flower is "irregular." The 

 back (upper) petal is large and broad (the 

 "banner"), the two lateral petals ("wings") are narrower 

 and hooded, while the two lower petals are still nairower, 

 united along their lower margins and much curved 

 upward (forming the "keel"). The green calyx is 



