Rosaceae

Rosaceae family.

A large, worldwide family whose classification, after many changes, is still not settled.
Different classifications are seen among various sources.

The family includes many economically important genera used as food, garden ornamentals,
    cut flowers plus a few used for wood. Some, such as Cotoneaster can be weeds.

Foods include Malus – apples; Pyrus – pears; Prunus – plums, prunes, peaches, apricots, nectarines and almonds;
    Cydonia – quinces; Rubus – blackberries and raspberries; Fragaria – strawberries and Eriobotryia – loquats.
Garden plants and/or cut flowers include Rosa – roses, Sorbus, Photinia, Kerria, Cotoneaster and Pyracantha.

The estimated number of genera is about 90 (60 – 125).
The estimated number of species varies from 2000 to nearly 5000.
Australia has 23 genera mostly introduced.

Part of the problem with species numbers is that many plants can produce seed without being fertilised (apomixis).
An extreme example is the Rubus genus that could have from a few hundred to thousands of species.

Earlier classifications recognised 6 subfamilies (sometimes treated as families themselves) – Rosoideae,
    Spiraeoideae, Maloideae (Pomoideae), Amygdaloideae (Prunoideae), Neuradoideae, and Chrysobalanoideae.

Later classifications are into:
    a.) 3 or 4 families – Amygdalaceae, Malaceae, Rosaceae, +/- Spiraeaceae.
    b.) 4 subfamilies Amygdaloideae, Maloideae, Rosoideae and Spiraeoideae.
    c.) The above 4 have also been reduced to 3 subfamilies in a more strictly defined Rosaceae.

1. Subfamily Amygdaloideae.
A larger subfamily including the former Amygdaloideae, Spiraeoideae, and Maloideae.
The fruit are fleshy drupes or pomes.
It includes Chaenomeles, Cotoneaster, Crataegus, Cydonia (quinces), Eriobotrya (Loquats), Kerria, Malus (apples),
    Photinia, Prunus (with almonds, apricots, cherries, nectarines, peaches and plums), Pyracantha,
    Pyrus (pears), Rhaphiolepis (Hawthorn), Sorbus and Spiraea.

2. Subfamily Rosoideae.
These have dry, indehiscent fruit (achenes), aggregate fruits of many drupelets or dry fruit dehiscing on one side (follicles).
There are over 40 genera and 850 species including roses, raspberries and strawberries.

3. Subfamily Dryadoideae.
Four genera whose fruits are achenes with hairy styles.

J.F.

Genus