308 PHYLUM XIV. ANTHOPHYTA 
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 
2) 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 Fig. 185. 
back (upper) petal is large and broad (the oe 
“banner’’), the two lateral petals (‘‘wings’’) are narrower 
and hooded, while the two lower petals are still narrower, 
united along their lower margins and much curved 
upward (forming the “keel”). The green calyx is 
Fie. 184.—Prunus. 
