Stem, Leaf, and Flower 



The leaves of many grasses are twisted (to the right in 

 some species, to the left in others), as twining plants twist with or 

 against the sun. It is said that the leaf blade in a few grasses is 

 sensitive, and slowly folds together when briskly rubbed. 



In dry weather and in dry soil it will be noticed that the leaves 

 of certain grasses are rolled tightly, becoming involute, as it is 

 called. As the cells on the upper surface of the leaf lose their 

 moisture and contract under a burning sun the edges of the leaf 

 curl inward until the stronger cuticle of the lower surface is outer- 

 most, and thus an added protection is given against an excessive 

 loss of moisture. The response to the external stimuli of heat 

 and cold, of light and darkness, in the vegetable world is exquis- 

 itely delicate. In the growth of plants, in their "sleep" at night, 

 and in their many so-called "adaptations" to varying conditions, 

 the student may read the life of Nature in an ever open book. 



INFLORESCENCE 



A spike is formed when the spikelets are apparently sessile on 

 the main axis — e. g.. Couch-grass. 



A Panicle is formed when the spikelets are on secondary or 

 further-divided branches ■ — e. g.. Orchard Grass and Old Witch- 

 grass. 



The Rachis is that part of the stem on which the spikelets or 

 spikelet-bearing branches are borne. 



The small flowers of the grasses bear little resemblance, at first 

 glance, to the distantly related lilies; yet if some of the lilies that 

 bloom in spikes were to crowd their flowers more and more, and 

 were to reduce their petals to mere scales, such plants would be well 



19 



