Leaves Not Lobed
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Leaves with smooth margins, often referred to as "entire," or with slightly wavy edges.

Leaf margins with fine, double teeth, that is with teeth between the vein ends

Leaf margins with coarse teeth, that is with a single tooth at the end of each vein

Leaf margins with rounded teeth

Leaves varied, and sometimes confusing. You must look at the branches for the presence of long sharp thorns
Hawthorn