BRITISH CEREALS. 



being no funiculus, or stalk, the hilum indicates the position 

 of the micropyle, the ovary being what is known as hemitropous, 

 that is half inverted. Sometimes the hilum is round, sometimes, 

 as in this case, it is long, but so strictly does it maintain its 

 shape through whole groups of genera, that it has its uses in 

 classification. 



On the opposite side, that facing the outer palea on the 

 plant, is the embryo. This is near the base of the grain and is 

 visible through the pericarp, as the outer covering is called, 

 coating which on the inside is the aleurone layer. The grain is as 

 a rule a caryopsis, that is a dry fruit, or nut, in which the seed 

 instead of being free, as in an achene, is joined to the outer cover- 

 ing, the other contents being the endosperm, or nutriment of the 

 embryo, which forms the bulk of the grain, and, when ground, is 

 known to us as flour. In some grasses, none of them British, the 

 seed is loose and in due time falls out ; and in two or three genera 

 of the Bambusae the fruit is a berry, which in one species, Melo- 

 canna bambusoides, may be from four to six inches in diameter. 



Backing against the endosperm is the scutellum, through 

 which its absorption is effected, and in front of the scutellum are 

 the embryo with the plumule, or bud of embryonic leaves, by 

 which the plant rises above the ground, and the radicle from which 

 the roots come. In front of these, up against the pericarp, is, 

 when present, the small scale known as the epiblast. The plumule 

 is on a, sometimes indistinct, stem known as the epicotyl ; and 

 the radicle is enclosed in a sheath, the coleorhiza, which the 

 roots burst through as soon as they begin to grow. 



Some authorities consider the scutellum to be the cotyledon ; 

 others say that the scutellum and first sheathing leaf form the 

 cotyledon ; a few tell us that the epiblast represents a second 

 cotyledon, a rather awkward suggestion, as it might make our 

 plant a dicotyledon. 



When growth begins the radicle gives forth, the primary root 

 soon followed by the adventitious roots ; and the plumule, by 

 the shortest way, as in Rye and Wheat, or by the longest, as 

 in Oats and Barley, emerges from the grain, and, as a pencil of 

 rolled leaves, known as the spear, pushes its hard point in a 



