| The leaf shape, color and spininess of English holly are all highly variable. |
| Evergreen leaves are simple, alternate, glossy, leather-like and vary in marginal spininess. |
| A notable tendency in the family is its members' adaptations to dry climates: small and crowded leaves, shortened branches, thorniness or spininess, and a low, shrubby, intricately branched habit. |
| Leaf spininess is highly variable from clone to clone, from complete spininess to very few spines. |
| Ecotypes have also been shown to vary in spininess, flower colour, seed size and time of emergence. |
| In general, the spininess of the clinkers is inversely proportional to both the thickness of the clinker layer and of the flow itself. |
