2064 A TEXTBOOK OF THEORETICAL BOTANY 



which includes all the cereal crops, may be considered as one of the most 

 economically valuable families of Flowering Plants. We shall consider the 

 Gramineae in detail but will first discuss the Juncaceae and the Cyperaceae. 

 The Juncaceae are perennial or annual herbs, very rarely shrublike, 

 often with adventitious roots and producing horizontal or sub-erect 

 rhizomes. The stems are usually leafy only at the base and the leaves are 

 linear or filiform with a sheathing base. The flowers are produced in 

 panicles, corymbs or dense heads. They are often very small and may 

 be hermaphrodite or unisexual. The perianth consists of six segments, in 

 two whorls, which are usually green or reddish in colour. There are either 

 three or six stamens inserted opposite the perianth segments. The ovary is 

 superior and is either trilocular with axile placentation or unilocular with 

 parietal placentation. The fruit is a dry capsule and the seeds are sometimes 

 tailed with a dryarillate appendage. The family is of world-wide distribution 

 mostly in temperate regions. There are seven genera, among which by 

 far the greater number of species is included in the genus yiinais (Fig. 2002). 



Fig. 2002. — jfuncus effusus. Common Rush. 

 Inflorescences. 



This genus, with about 225 species, occurs all over the world in cool, damp 

 places. Eighteen species or more occur in Britain. They possess sympodial 

 rhizomes bearing one leafy shoot each year and produce cymose heads of 

 small flowers which are protogynous and are pollinated by wind. 



Rushes are used in making baskets and chair seats. J. squarrosus, which 

 is common in the hill pastures of Britain, is a valuable fodder for sheep. 

 J. effusus is chiefly used in the preparation of Split Rush for basket work. 



