Distinguishing Impatiens capensis from Impatiens pallida (Balsaminaceae) using leaf traits

Impatiens capensis (orange jewelweed) and Impatiens pallida (yellow jewelweed) are annual species with similar phenotypes that grow in similar environments throughout the eastern United States. This makes them extremely difficult to distinguish when (chasmogamous) flowers are absent. We use morphometric analyses to identify leaf characters that distinguish these species. After collecting and scanning 342 leaves from plants of each species growing in co-occurring populations in Madison, WI, we quantified: leaf size, shape (using elliptical Fourier analysis), serratedness, and color. Using leaf size and shape traits, a linear discriminate analysis assigned up to 100% of leaves to the correct species. The uppermost fully expanded leaf yielded the most accurate species assignments based on size and shape traits. This leaf was on average, smaller, less deeply serrated, with a more acute base, apex, and elliptical shape in I. capensis as compared to I. pallida. Impatiens pallida leaves had mo...

Impatiens capensis（橙色凤仙花）和Impatiens pallida（黄色凤仙花）是一年生物种，表型相似，且在美国东部各地的相似环境中生长。这使得在（开放传粉花，chasmogamous）缺失时，二者极难区分。我们采用形态计量分析来识别可区分这两个物种的叶片特征。在威斯康星州麦迪逊市的共生种群中，我们从每个物种的植株上采集并扫描了342片叶片后，对以下特征进行量化：叶片大小、形状（采用椭圆傅里叶分析，elliptical Fourier analysis）、锯齿度和颜色。利用叶片大小和形状特征，线性判别分析（linear discriminate analysis）可将高达100%的叶片准确归类到对应物种。基于大小和形状特征，最顶端完全展开的叶片在物种归类中准确率最高。与Impatiens pallida相比，Impatiens capensis的这类叶片平均更小、锯齿更浅，叶基和叶尖更尖锐，且形状更接近椭圆形。Impatiens pallida的叶片则具有更...