A repository of lncRNAs annotated in 37 plant species and six algae. By using the same pipeline to annotate lncRNAs we make it possible to compare lncRNA sequences and distribution from different species. By organizing the sequences in a central database we aim to provide a tool for the scientific community that can boost research on this class of transcripts. The GreeNC database provides information on sequence, genome coordinates, coding potential and folding energy of the lncRNAs. GreeNC includes ∼200 000 pages with information on >190 000 transcripts from 37 plants and six algae. More than 120 000 transcripts were annotated as high confidence lncRNAs, 30% of them from the T. aestivum (17.8%) and Z. mays (8.2%). The lowest number of lncRNAs was annotated in the three algae C. rehinardtii (0.1%), M. pusilla (0.15%) and O. lucimarinus (0.16%). More than 25 000 and 8000 transcripts were annotated as repetitive elements and miRNA precursors, respectively.