Division: Magnoliophyta
Class: Magnoliopsida
Order: Rosales
Family: Rosaceae
Subfamily: Maloideae 
Tribe: Maleae 
Genus: Malus (about 35 species)
Common name: Crab apple

Malus is a genus of about 30–55 species including the domesticated apple (Malus pumil).  
Crab apples are popular as compact ornamental trees, providing blossom in spring and colourful fruit in autumn. The fruits often persist throughout winter.
Crab apples can be any wild varieties of the garden apple tree Malus pumil. Crab apples generally yield small, bitter fruit (in comparison to domestic apples, Crab apples have only about 8 calories. They are small, extremely tart fruits. Some botanists believe that they may be the survivors of the wild ancestors of the domesticated apple. The fruits and their trees look remarkably like apples, which can lead to unfortunate confusion, as the taste of crab-apples is rather distinctive and often unpleasant on its own. 

Crab apples are a species of deciduous trees and shrubs from the woodland and thickets of Europe, Asia and North America. In most species, the fruit is astringent and acidic and is not palatable when raw.  The small fruits are high in pectin, a natural fruit-based gelatine, and when they are cooked with a liberal helping of sugar, they develop a rich, flavourful, very tart ruby red jelly. Crab-apple jelly may be cut with other ingredients or used plain. It is often paired with toast, scones, and other baked goods.

Crab apples 1 .JPG 

Crab apples 2 .JPG 

1-Crab apples -002.JPG

The tree below can be seen from the bridge east of Waiwaka Reserve at Lat 39 3' 33.747 S: Long 174 5' 41.715 E Photographed April Malus cultivar Crab apple .JPG

Crabapples-002.JPG

Two trees of a species of Malus with thorns at Adams point. The fruit is small about cherry size,  
Found at Lat 39 3' 43.405 S Long 174 5' 34.65 ECrab apple with thorns at adams point.JPG

A species with cherry-like like fruit
Crabapple with spines -2.JPG

The above trees spines 
Crab apple with thorns at adams point-1.JPG 

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/