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Rosaceae
| The Rosaceae are trees, shrubs and herbs comprising about 100 genera and 3,000 species. Most species have alternate leaves and stipules. These may be adnate to the petiole. You have likely heard the saying, "a rose is a rose is a rose," suggesting that when you've seen one, you've seen them all. The family does tend to have somewhat monotonous actinomorphic flowers, commonly with 5-parted perianth and numerous stamens. However, closer inspection reveals that the gynoecium varies tremendously among different species of the family. In the subfamily Rosoideae many apocarpous pistils mature into achenes while in the Prunoideae a single monocarpellate pistil matures into a drupe. In subfamily Spiraeoideae the gynoecium consists of two or more apocarpous pistils that mature into follicles. In all of these cases the ovary is superior and there is commonly some development of a perigynous zone. However, in a fourth subfamily, Maloideae, the ovary is compound and inferior, and an epigynous zone may occur. |
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