size) and a unit pattern governing the entire pattern (i.e., single-leaf size) showed power-law dependence on developmental stage (t). Discussion Our results can further improve current metabolic theories of plant ecology. Specifically, current theories predict total leaf number (t) as a power function of total plant mass (M) [i.e., d t = k1M ], and predict whole-plant leaf area (F) by assuming that F is proportional to t [16]. Our power-law results can be incorporated into these models as follows: t~k1M d and F ~k2tb, so that F ~k3M bd 2 ð Þ The dynamic scaling (Fig. 3) implies that the proportion of large (or small) leaves on a relative scale within a given plant is basically invariant among different-sized plants. In addition, within the largest C. cordatum plants, large leaves defined the canopy structure with small leaves filling the spaces between large leaves (Fig. 1). Accordingly, the overall canopy structure of large plants was similar to that of small plants (Fig. 1). These two phenomena, conservation of overall structure across developmental stages (i.e., dynamic scaling law), and the filling of spaces between large units with small units, are basic properties of fractal growth phenomena [31], and have been core assumptions of several models of plant allometry [4,6,7,32]. Some models of plant development (e.g., the L-system [33]) can simulate fractal growth, in which idealized successive branching processes result in geometric similarity among different-sized plants across developmental stages. We observed the same properties for a plant species without an explicit, fractal-like hierarchical branching structure. The same basic template organizing plant form applied across developmental stages, facilitating conservation of efficiency of the light-capturing foliar array and mechanical stability. These results suggest the possibility of a form-balancing hypothesis, which predicts that scale invariance through development will be widespread in plants. 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