Grass climatic and anatomical data

Members of the grass family Poaceae have adapted to a wide range of habitats and disturbance regimes across the planet. The cellular structure and arrangements of leaves can help explain how plants survive in different climates, but these traits are rarely measured in grasses. Further, most studies are focused on individual species or distantly related species within Poaceae. While this focus can reveal broad adaptations, it also likely to overlook subtle adaptations within more closely-related groups (subfamilies, tribes). This study therefore investigated the scaling relationships between leaf size, vein density, and vessel size in five genera within the subfamily Pooideae. The relationship between leaf area and major vein number was consistent with previous findings (p < 0.05, slope = 0.72 +/- 0.24), as was the scaling coefficient of VLA (slope= -0.46 +/- 0.21). However, several genera exhibited novel anatomical relationships. In Poa and Elymus, minor vein number and leaf length were uncorrelated, whereas in Festuca these traits were positively correlated (slope = 0.82 +/- 0.8). These findings suggest there is important broad-scale and fine-scale variation in leaf hydraulic traits among grasses. Thus, future studies should consider both narrow and broad phylogenetic gradients.