以龙船花两变种橙红龙船花Ixora coccinea var. coccinea、邦德胡卡红仙丹草I. coccinea var. bandhuca的成熟叶为材料，利用WinFolia软件测定多项叶形态指标，并对叶面积进行回归分析，分别建立其8种回归方程以及总的适用回归方程。结果表明，龙船花两变种的叶片长×叶水平宽、叶周长、叶垂直长、叶片长、叶水平宽、叶片长×叶片长以及叶水平宽×叶水平宽与叶面积之间的相关系数及复相关系数均呈极显著水平(P＜0.01)，可分别用来建立龙船花的叶面积回归方程；叶面积与叶片长×叶水平宽的相关系数及复相关系数最高，基于叶片长×叶水平宽的8种叶面积回归方程更好地估测两种龙船花的叶面积。经检验发现，二次函数、复合函数、幂函数能更准确地估测叶面积；由两种龙船花共同建立的3种总的回归方程中，复合函数与幂函数能更好地模拟估测叶面积。

Quick and non-destructive methods for estimating leaf area were important for future related research of Ixora. In order to estimate leaf area of two varieties of Ixora, mature leaves of I. coccinea var. coccinea and I. coccinea var. bandhuca were collected as the experiment materials. The WinFolia software was used to measure leaf shape indices such as leaf area(LA), leaf perimeter(LP), leaf vertical length(VL), leaf blade length(L), leaf horizontal width(W), LW, LL, WW, and L/W. The respective regression analysis between leaf area and other leaf shape indices of the varieties of Ixora were carried out by using 8 common regression models. Besides, the general regression equation that suitable for two Ixora varieties were established. The results indicated that the correlation and the multiple correlation coefficients between the leaf area and the leaf shape indices，such as LW, LP, VL, L, W, LL, and WW, were at extremely significant level (P<0.01); the correlation and the multiple correlation coefficients between the leaf area and LW were the highest, respectively; leaf area could be predicted better with LW by quadratic function, composite function and power function; among the three kinds of regression equations that both suitable for two Ixora varieties, the composite function and power function could be better to predict leaf area.