This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
Though unknown in a fossil state in Great Britain, this sedge is found in Prussia in the Birch, Pine, and Oak Zones, and in Gothland. To-day it ranges in the N. Temperate Zones from Gothland southward, N. Africa, Siberia. In Great Britain in the Peninsula province it grows only in W. Cornwall and N. Somerset; in the Channel province only in Dorset, Isle of Wight, S. Hants; in the Thames only in E. Kent; in Anglia not in Bedford; in the Severn province only in Worcester, Warwick, Stafford, Salop; in S. Wales it grows only in Glamorgan and Pembroke; in N. Wales in Carnarvon, Flint, Angle-sea; in the Trent province in Lincs; Chester in the Mersey province; in the Humber generally, except in N.W. Yorks; in the Tyne province, except in Northumberland; in the Lakes province, except in the Isle of Man; W. Lowlands, except in Renfrew and Lanark; in Berwick in E. Lowlands; Forfar in E. Highlands; in the W. Highlands it does not occur in Main Argyle, Dumbarton; W. Ross and W. Sutherland in N. Highlands. It is local in England from the Border southward. It is found also in Ireland.
Prickly Twig Rush is a characteristic bog plant which grows especially in lowland districts near the sea, and most uniformly in E. Anglia.
The first Greek name suggests (as does the English one) the rigid prickly character of the head of the plant. It has rounded stems, which are erect, stout, leafy, and smooth, with leaves which are long, rigid, 3-angled at the tip, rough on the margin.
The flowers are borne in a dense corymb-like compound cyme, axillary or terminal, which is contracted, the flowers being collected in dense spikes, 3 flowers in each. One nut only is fertile.
Prickly Twig Rush is 3 ft. in height. The flowers are in bloom in July and August. The plant is perennial, increased by division.
The flowers are pollinated by the wind, bisexual, or the lower male.
Photo. II. Irving - Prickly Twig Rush (Cladium Mariscus, Br.)
There are about two flowers, with one fertile above. There are 2 stamens, with anthers coming to a point. The style is swollen at the base, and falls eventually. There are 2-3 stigmas.
Reed Tussock (Loelia coenosa), a moth, is found upon Prickly Rush.
Cladium, P. Br., is from the Greek clados, a twig, and mariscus is Latin for a kind of rush.
The plant is also called Shere- or Shear-grass, Lesch, Sedge, and Twig Rush. Turner says as to the name Shear-grass: "The edges of thys herbe are so sharpe that they will cut a mannis hande and have a certaine roughness which maketh them to cut the sower, of which propertye the Northern men call it Sheregres. It hath a long stalke and thre square, and in the top of that is a sort of little knoppes instede of sedes and floures much like unto oure gardine gallingal. The people of the Fenne countreys use it in for fother and do heate ovens with it." It was used for lighting fires at Cambridge. In the East it was said to have formed the Crown of Thorns.
Essential Specific Characters: 324. Cladium Mariscus, Br. - Stem half round, smooth, leaves long, rigid, serrate, triquetrous above, flowers in a panicle of 1-3 spikelets.