392 



THE SEA SHORE 



being protected by scaly bracts. The seeds are produced in a case 

 called the ovary, and are fertilised by pollen grains which are 

 developed in the anthers. When the pollen grains are set free they 

 alight on the adhesive stigma, and grow, send- 

 ing their tubes down into the ovary. The 

 term monocotyledon is applied to these plants 

 because the embryo has only one cotyledon 

 or seed-leaf. 



The principal divisions of this group are 

 the Glumaceous Monocotyledons, in which 

 the flower has no perianth, but is enclosed in 

 scaly bracts or husks called glumes ; and the 

 Petaloid Monocotyledons, distinguished gene- 

 rally by the presence of a more or less con- 

 spicuous white or coloured perianth. The 

 first of these includes the rushes, sedges, and 

 grasses ; and the other contains the lilies and 

 orchids, with their allies, together with certain 

 aquatic and semi-aquatic plants. 



Among the Grasses there are several 

 species that show a preference for the imme- 

 diate neighbourhood of the sea, some growing 

 luxuriantly at the bases of the cliffs where the 



beach is sandy, and others thriving best in salt marshes ; but before 

 dealing with these individually we shall note the general character- 

 istics of the order (Graminece) to which they belong. 



Grasses are distinguished by their jointed stems, which are 

 usually hollow, with a split sheath, and bearing alternately arranged 

 narrow leaves. The flowers, which are disposed either in spikes 

 (sessile flowers arranged along a common axis) or in panicles 

 (flowers stalked and arranged as in fig. 281), consist of scale-like 

 bracts enclosing the stamens and the pistil. The bracts are in two 

 series, the outer usually consisting of two glumes, and the inner of 

 two pales ; the upper pale, however, has two ribs running through 

 it, and is therefore usually looked upon as a combination of two. 

 In some species both glumes and pales are absent ; but the former, 

 when present, enclose one or more flowers, among which may 

 be some that are abortive. The stamens are generally three in 

 number, attached to the base of the flower ; and the ovary is 

 superior or free, that is, it grows above the other parts of the 

 flower, and contains but one seed. 



FIG. 276 -LEAF OF 

 A MONOCOTYLEDON 



