Precipitation gradients, plant biogeography, and the incidence of drip-tips in Cerrado plant species
Queenborough, Simon; Sullivan, Megan K. (2020), Precipitation gradients, plant biogeography, and the incidence of drip-tips in Cerrado plant species, Dryad, Dataset, https://doi.org/10.5061/dryad.xsj3tx9bk
Data on leaf characteristics were collected using online herbarium specimens from Kew (K), New York Botanic Garden (NY), the Field Museum (F), and Missouri Botanical Garden (MO), Flora Neotropica, and Gottsberger & Gottsberger (2006). Most specimens were collected in Brazil; we obtained 1–17 specimens per species (median = 2). Excluding two leafless tree-like Cactaceae, we found leaf size and tip data for 845 of the remaining 846 species. We were unable to locate specimens of Mezilaurus mattogrossensis (Lauraceae).
Leaf tip characteristics vary continuously across species (Gentry 1969). Furthermore, intra-specific variation in leaf form is common in some species but not others. To ensure consistency with previous data from Amazonia, we scored leaf tip type for each species as one of five ordinal categories: retuse, rounded, acute, small tip, and drip-tip, following Malhado et al. (2012) (Fig. 1 and SI Fig. 1) using the most abundant tip type observed in the specimens. To reduce variability that could be associated with observer bias, all images were assessed by the lead author (MKS). Because leaf tip can vary with leaf size, we classified leaf size into one of seven size categories using Webb’s (1959) modification of Raunkiaer’s (1934) method (sensu Malhado et al., 2009).