This paper examinines the relationship between latitude, altitude, humidity, and leaf size.
Helps explain differences in the way indicas and sativas grow – sativas were typically found in more humid environments, while indicas tended to appear in more arid environments. Also explains why ruderalis is so small – it’s so dang cold where it’s naturally found.
Larger leaf size in the tropics is often a result of the location of the plant. Larger leaf sizes in understory plants plants is a result of adaptation to maximize absorption of light. I have grown pepper clones in high light and low light conditions and the leaves are larger in the low light conditions.
