182 THE BOOK OF NATURE STUDY 



The veins run parallel in it. We thus find the leaves to consist 

 of a large sheath and a blade, without any intervening leaf-stalk. 



If the stem be cut in half through a node (Fig. 85, 3) it will be 

 seen that the long internodes are hollow, while the nodes are solid. 

 It will also be clear that the swelling at the node is due to the 

 leaf-sheath and not to the stem. The lower region of the inter- 

 node is very delicate, and continues in a growing condition for a 

 long time. The swelling of the leaf-sheath at the node explains a 

 familiar power of many grasses. Everyone has noticed that when 

 a part of a field of hay has been laid flat by heavy rain a certain 

 amount of recovery is possible. The lower parts of the shoots 

 may remain flat on the ground, but the ends turn up and become 

 erect. This sharp curvature of the stem is due to the swollen base 

 of the leaf-sheath starting to grow on the lower side when dis- 

 placed from the vertical position. 



Above the uppermost foliage-leaf comes a long bare region of 

 stem which is slightly flattened. This ends in the inflorescence, 

 small groups of flowers or spikelets being attached alternately on 

 opposite sides of the main stem. The side of the latter against 

 which the edge of one of the flattened spikelets lies is somewhat 

 grooved, so that when the spikelet is young it is protected by the 

 main stem on this side. A single spikelet must be very carefully 

 examined in order to make out the position and structure of the 

 flowers. For this purpose one with open flowers should be 

 selected ; this will be recognised by the anthers of the stamens 

 hanging out from it. In such a spikelet the various parts can be 

 seen with little difficulty and hardly any dissection. 



Each spikelet (Fig. 85, 4) evidently represents a lateral branch 

 of the main stalk, and bears a number of green leaves or bracts of 

 peculiar shape. These enclose and protect the flowers. Lowest 

 of all, on the outer side of the spikelet, so that this appears to 

 stand in its axil, is a bract between which and the main stem the 

 young spikelet was enclosed. This is called the glume. In the 

 lateral spikelets there is no corresponding bract on the opposite 

 side, for here the spikelet was protected by the stem. But in the 

 spikelet which terminates the inflorescence two glumes will be 

 found enclosing the rest of the spikelet between them. This 

 is the condition most commonly met with in the spikelets of 



