Herbs with tuberous rhizomes, large radical usually net-veined leaves, and spatbaceous inflorescence. Flowers on a spadix, unisexual or hermaphrodite. Perianth none, or consisting of 4 to 8 hypogynous divisions. Stamens definite or indefinite. Fruit baccate, one- or more celled, one- or more seeded. A large order containing about 100 genera and 1,000 species, chiefly inhabiting tropical countries. We have three representatives in our native flora. The commonest is Arum maculatum, Lords-and-Ladies, or Cuckoo-Pint. A. Itdlicum has only been observed in the South of England. A corns Calamus, Sweet Flag, has equitant ensiform leaves and a tall compressed spathaceous scape, and a lateral spadix crowded with very small bisexual flowers. It is rare and local in England. The species worth introducing into the flower garden are limited in number.