400 



THE SEA SHORE 



The true rushes belong to the order Juncacece. These have 

 fibrous roots and narrow leaves, and bear clusters of brown flowers. 

 The perianth consists of six parts, and the stamens are usually 

 six in number. The ovary is generally three-celled, developing 

 into a three- valved capsule. The Lesser Sea Hush (Juncus mari- 

 timus) is common in salt marshes, growing to a height of two or 

 three feet, and flowering in July. It has a rigid leafless stem, 

 bearing lateral clusters of flowers. The segments of the perianth 

 are very narrow and sharp, and the seeds are enclosed in a loose 

 testa. Closely allied to this species is the Great Sea Bush 

 (<7. acutus), which grows three or four feet high on sandy shores. 

 In general characteristics it resembles J. maritimus, but the 



FIG. 283. THE 

 SEA SEDGE 



Fro. 284. THE CURVED 

 SEDGE 



FIG. 285. THE 

 GREAT SEA BUSH 



segments of the perianth are oval and have thin transparent 

 margins ; and it is a much rarer species. 



We now pass to the peculiar Sea Grasses or Grass Wracks 

 (Zostera) which grow in salt water. They belong to the order 

 Naiadacece, and are characterised by cellular leaves with parallel 

 veins, and inconspicuous unisexual or bisexual flowers. The 

 perianth, when present at all, consists of two or four scale-like 

 parts, and the stamens correspond in number with these. The 

 ovary is free, and the carpels, one or more in number, contain each 

 a single ovule. In Zostera the flowers are imperfect, and seem to 

 grow in the slit of the leaf. There are two species, both of which 

 grow in shallow water close to the shore, often in such dense 

 masses that they impede the progress of boats. They have long 



