how to tell Midland Hawthorn from Hawthorn
Hawthorn (Crataegus monogyna), above.
Very common everywhere in the UK, and also much planted. Loves chalky as well as most other soil-types. Prefers well-drained and sunny locations, where it is often spectacularly floriferous. Even writhing with cream, as in some of Hockney's paintings.
Midland hawthorn (Crataegus laevigata), below.
Native only to south-east-central England, and always less common than C. monogyna. Prefers heavier soils and tolerates more shade. Flowers a couple of weeks earlier. Often planted outside its native range, usually by mistake for C. monogyna, except in its various decorative forms such as the popular double-pink 'Paul's Scarlet'.
Both species are very variable and will hybridize with each other and with any other Crataegus in the vicinity (e.g. the American Cockspur-thorns).
Leaves of C. monogyna (above) and C. laevigata (below). The former is more deeply lobed and is toothed only at the ends of the lobes. The latter is toothed round most of the margin.
The flowers - C. monogyna above, C. laevigata below. As its Latin name says, the former has only one style per flower. The latter has two.
And the berries - strictly, pomes - (photos from late September) - C. monogyna above, C. laevigata below. Nothing much to differentiate these, but the leaves tell the story.
Nothing much, that is, until you break them open and extract the stony seeds (a smeary, messy business). As you'd expect, C. monogyna has only one (below left), whereas C. laevigata has two together, like the two halves of an orange (below centre and right).
The young leaves when they emerge are well-known as a good wild food. The "berries" are an excellent raw and wild food, too. If you are eating for bulk, rather than a tidbit, then a bland favour is best - most berries are too sugared and will give you the squits if you gorge on them. Besides, the somewhat buttery texture of hawthorn "berries" suggests to me that they may be comparatively rich in fat content; and fat means warmth.