SPARGANIUM IN BRITAIN

started to prepare a more comprehensive monograph. Unfortunately Rothert suffered the tragic fate of so lllany elderly Polish and Russian scientists in the Russian Revolution and his work seems to have been lost. In 1911, however, he visited the herbaria at Kew and the British Museum and wrote notes on many of the herbarium sheets. I have used these notes as a guide to the taxonomy. SPARGANIUM L., Sp. PI., 971 (1753). Glabrous aquatic (occasionally semi-terrestrial) perennial herbs, reproducing vegeta-tively by long, thin, underground rhizomes. 'Stems simple or branched. Leaves linear, distichous, sheathing at the base, erect or floating. Flowers unisexual, crowded into separate globose capitula, the female capi.tula towards the base in each inflorescence; perianth of 3- 6 radiate scales; male flowers of 3- 8 stamens, the filaments sometimes partially united; female flowers of one, occasionally two, rarely three, fused carpels with a single style persisting in fruit, and as many stigmas as carpels. Fruit drupaceous with a dry, spongy exocarp, and a hard endocarp; seed albuminous, with a large embryo. Pollination mainly by wind. There are about fifteen species in the North Temperate regions, extending from sub-arctic Scandinavia and North America to the Mediterranean and Mississippi Basin; the distributional belt stretches across North America, Europe, and Asia to Japan. Two specie