2074 



A TEXTBOOK OF THEORETICAL BOTANY 



spike-like racemes. Glumes well developed, outer paleae five- 

 to indefinitely nerved, awnless or avvned from the tip. 

 Lodicules two. Stamens three. Styles two. Fruit a caryopsis, 

 free or adhering to the inner or outer palea. 



The tribe includes ten genera which are distributed in temperate regions 

 mainly in open grassland. Many are in cultivation. 



Among the more important genera are Agropyron, Triticitm, Hordeum, 

 Elymus, Secale. All, except the last, are found in Britain. Of these, Triticum 

 (Wheat), Hordeum (Barley) and Secale (Rye) constitute the most important 

 of the cereals. The modern cultivated varieties have been obtained from 

 wild species found growing mainly in south-western Asia. We shall discuss 

 the question more fully in Volume IV under Economic Botany. Some 

 species of Agropyron and Elymus make good fodder grasses. 



The genus Lepturus and several allied genera, which occur in warm 

 temperate regions and along the seashore in the tropics, are placed by 

 Hubbard in a separate tribe, the Leptureae. 



4. Arundineae. Perennials with tall, stout, sometimes woody stems 

 bearing long, flat leaf blades. Spikelets (Fig. 2010) herma- 



I 



Fig. 2010. — Phiagmites. A, Flower. B, Spikelet. Agropyron. C, Flower. 



D, Spikelet. 



phrodite or unisexual with sexes on different plants, two- to ten- 

 flowered, often arranged in large panicles. Glumes hyaline or 

 membranous, both similar or the lower ones smaller. Outer 

 paleae similar to the glumes, acuminate and either awnless or 

 awned from the tip, one- to five-nerved; enveloped in long 

 hairs arising from the back of the paleae in fertile florets or from 

 the rachilla. Lodicules two. Stamens two or three. 



