design: Leaves from 7 to 20 plants (mean = 12) of L. longirostris were collected at 21 localities following three south-to-north transects across the Iberian Peninsula (western, central and eastern, resulting in a total sample size of 248 individuals. An additional sample from northeastern Iberia was used to generate the genome draft. We also sampled 20 individuals of the close relative L. saxatilis from two localities in northern Iberia to be used as outgroup. High quality genomic DNA was isolated from 50 to 100 mg of dry leaf material using the DNeasy Plant Mini Kit (Qiagen, Hilden, Germany) following standard protocols.