Grass genus of the family Poaceae; toxic when infested with anguina lolii, clavibacter toxicus, Neotyphodium, Pithomyces, endoconidium temulentum or may contain toxic amounts of nitrate. Includes L. multiflorum (L. italicum, Italian rye grass), L. perenne (perennial rye), L. rigidum (Wimmera rye grass), L. temulentum (darnel, drake).
- L. perenne — a staple grass for permanent pastures. It is not in itself poisonous, except that it does contain high concentrations of alkaloids, e.g. perloline, at some times and may accumulate nitrate. There are doubts about the pathogenicity of these compounds. The diseases that do occur on perennial rye grass pastures are
ryegrass staggers and facial eczema. Called also perennial ryegrass. - L. rigidum — an annual pasture grass of great productivity. Its seeds may be parasitized by a gall-inducing grass nematode Anguina lolii, and if it is accompanied by a Clavibacter toxicus which produces tunicaminyluracils (corynetoxins), it is very poisonous. Ataxia, convulsions and death are the common signs. Called also Wimmera rye grass.
- L. temulentum — varying reports on the toxicity of this grass may be because the poisoning is due to a fungal infection, e.g. Endoconidium temulentum. Called also darnel.
