Rosaceae - Definition and Overview

Rosaceae
Rosa arvensis
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Rosales Family: Rosaceae
Subfamilies
Rosoideae Spiraeoideae Maloideae Amygdaloideae or Prunoideae

The Rosaceae or rose family is a large family of plants, with about 3,000-4,000 species in 100-120 genera. It is divided into four subfamilies, mainly on the basis of how the fruit develops:

• Subfamily Rosoideae: Many small fruits, each of which is an achene or drupelet, and often the fleshy part of the fruit (e.g. strawberry) is the hypanthium or the stalk bearing the carpels. Rose, blackberry, raspberry, strawberry.
• Subfamily Spiraeoideae: A non-fleshy fruit consisting of five capsules. Spiraea.
• Subfamily Maloideae: Five capsules (called "cores") in a fleshy endocarp, surrounded by the ripened stem tissue. This structure is called a pome (after the French name for an apple, pomme). Apple, hawthorn, pear, quince, rowan.
• Subfamily Amygdaloideae (or Prunoideae): A single drupe with a seam, two veins next to the seam, and one vein opposite the seam. Plum, peach, almond, cherry.

A tongue-in-cheek poem

The rose is a rose
and was always a rose;
But the theory now goes
That the apple's a rose,
And the pear is, and so's
The plum, I suppose.
The dear only knows
What will next prove a rose.
You, my love, are a rose,
but were always a rose.

- Robert Frost, "The Rose Family"

External link

• University of Illinois - Rosaceae (http://www.life.uiuc.edu/plantbio/260/Rosaceae/Rosehome.html)