490 



PART IV. CLASSIFICATION. 



Tribe 6. Agrostidece : spikelets l-flo\vered, in panicles : glumes 2. 

 In Agrostis, the Bent-Grass,- the axis of the spikelet is glabrous, or it 

 baars short hairs ; A. vulgaris and alba are common in meadows : Apera 

 Splca Venti is common in fields : in Calamagrostis, the Small Reed, several 

 species of which occur on the banks of rivers and in woods, the axis of the 

 spikelet is covered with long hairs. Stipa pennata, the Feather-Grass, has 

 a long hairy awn. Milium effusum, Millet-Grass, without an awn, is 

 common in woods. Amongst the forms with dense cylindrical panicles, 

 Alopecurus, the Fox-tail Grass, has the glumes coherent at the base, and 

 one rudimentary palea. Phleum, the Cat's-tail Grass, has free glumes 

 and two distinct paleae. Phleum pratense is commonly known as Timothy- 

 Grass. 



Tribe 7. Avenece : the pani- 

 culate, or rarely spicate, spike- 

 lets consist of several (usually 

 two) flowers one of which is 

 sometimes $ ; the glumes (or 

 one of them at least) are as 

 long as the whole 'spikelet, 

 longer than the inferior paleae, 

 which usually have a long 

 twisted or bent awn. 



A vena, the Oat-Grass, has 

 loose panicles, and a two- 

 toothed inferior palea ; of this 

 genus there are many species ; 

 A.fatua (Wild Oats, or Havers), 

 pratensis and pubescens, are 

 common in cornfields and 

 meadows. The following 

 species are cultivated : A. sa- 

 tiva, the Oat (Fig. 302.4), with 

 its panicles in various planes ; 

 A. orientalis, with its panicles 

 in one plane ; A. atrigosa, with 

 a hairy floral axis ; and A, 

 nuda, the spikelets of which 

 usually consist of three flowers. 

 Trisetum (Arena) flavescens, the 

 yellow Oat-Grass, with a free fruit, occurs in pastures. Aira (Deschampsia) 

 c.cespitosa, a.ndflexuosa, Hair-Grasses, have truncate inferior palese, and are 

 common in meadows and woods. Holcus, the Honey-Grass, has spikelets 

 consisting of two flowers, the upper of which is usually <? , and the leaf- 

 sheaths are covered with silky hairs ; it is common in damp meadows. 

 In Arrheuatherum, the False Oat-Grass, the lower of the two flowers is $ . 

 Tribe 8. Fe&tucece: the spikelets are usually many-flowered, and the 

 glumes shorter than the inferior palese which either have 110 awn or a 

 straight terminal awn. Melica, the Melic-Grass, has sometimes spikelets 



FIG. 302. A Panicle of Oat, Avcna sativa : s main 

 axis; ' lateral axes; a spikelet (i nat. size). B 

 Spike of Wheat: s axis; g the depressions in 

 which the spikelets (a) lie. These are removed 

 at the lower part. 



