Holcus (soft-grass or velvetgrass) is a genus of African and Eurasian plants in the oat tribe within the grass family.Holcus species are used as food plants by the larvae of some Lepidoptera species including Coleophora lixella.Species Holcus annuus - Mediterranean and nearby areas from Portugal + Morocco to Caucasus Holcus azoricus - Azores - possibly a hybrid of H. lanatus and H.