The Rose family has 4000 species in 90 genera). Rosa is the ancient Latin name for the rose shrub and for the colour pink. The family is divided into three sub-families but with most (3000 species) in two sub-families – Rosoideae – which includes potentilla, rose, blackberry, raspberry, strawberry, meadowsweet and agrimony and Amygdaloideae – which includes hawthorn, apple, medlar, pear, blackthorn, cherry, flowering cherries, bird cherry, peach and almond. The flowers of the Rose family always have some form of hypanthium – an extension of the receptacle which may range from cup-shaped to flat, see photo below right. One result of this is that the family has many different types of fruit, some dry (achenes) but most fleshy. Where the hypanthium completely surrounds the ovaries and becomes part of the fruit it is is a pome as in the Apple. Where the hypanthium is open, as in the photo of the Cherry below, the fruit is formed from the ovary wall only and is a drupe.
Basic Flower Parts – 5 Sepals, 5 petals, 1 to many Stamens, 1 to many Carpels. Superior or Inferior Ovary in Hypanthium, Some sub-families have Nectaries. Fruit is an achene (potentilla), drupe (blackthorn, cherry, peach, plum, apricot), pome (apple pear, hawthorn), accessory fruit (rose hip, strawberry) or aggregate fruit. (blackberry).