Is leaf size a factor in determination of the rate of transpiration in Canna indica and Euphorbia milii?

Two ornamental plants, namely Canna indicia and Euphorbia milii were subjected to four watering frequencies viz. daily, weekly, biweekly and monthly, each with five watering regimes (1.25%, 2.5%, 5%, 10% and 20%). After six weeks of watering, leaf area and transpiration rate of the seedlings were determined. The leaves were larger in C. indica ranging from (105 mm²-436 mm²) than in E. milii (36 mm²-142 mm²) while transpiration rates were higher in E. milii (1.78x10⁴ mol/m⁻²/sec⁻¹-2.56x10⁻³ mol/m⁻²/sec⁻¹) than in C. indica (2.48x10⁻⁴ mol/m⁻²/sec⁻¹-3.70x10⁻⁵ mol/m⁻²/sec⁻¹). Leaf area has no effect on the rate of transpiration in these two plants, but absence of evidence of transpiration on the adaxial surface of leaves of E. milii suggests that other anatomical features such as stomata rather than the leaf area might determine the rate of transpiration in plants.