Tweedy, Ruth; Shi, Sarah; Uno, Kevin (2026): n-Alkane Distributions of Modern Plants from Kenya and Niger [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.995255

This dataset comprises plant wax n-alkane concentrations (C₂₅ - C₃₅) and corresponding relative abundances for 148 modern African angiosperm samples, including trees, shrubs, grasses, herbs, vines, and palms. Samples were collected from three regions: Samburu National Reserve (SNR) in Kenya (n = 99), Lothagam in Kenya (n = 1), and multiple locations across Niger (n = 48). The SNR samples were collected between October 2001 and August 2002 and include repeated sampling of the same individual plants, allowing assessment of temporal variability in n-alkane distributions. The Lothagam and Niger samples were collected in April and November 2019, respectively. All specimens were identified to at least the family level, with most resolved to genus or species, and are accompanied by metadata including plant functional type and photosynthetic pathway. Sample preparation and analysis were conducted at Lamont-Doherty Earth Observatory between 2018 and 2021. n-Alkanes were quantified using gas chromatography with a mass selective detector (GC-MSD) and flame ionization detector (FID). Response factor corrections were applied to peak areas to obtain concentration values. Odd-carbon-number n-alkanes (C₂₅ - C₃₅) were normalized to unit sum to generate relative abundance distributions. Trees, shrubs, and grasses from this dataset formed part of the training and validation data for Tweedy et al. (2026), where machine learning models differentiated African woody and grassy samples with up to 89% validation accuracy. The 19 herb, palm, and vine samples included here are unique to this dataset and not published elsewhere. This dataset provides a reference for evaluating n-alkane chemotaxonomic signals and supports applications in vegetation reconstruction.