6o 



THE TRIBES AND THEIR GENERA. 



Agropyrum. Spike stout. Spikelets solitary, quite sessile, 

 with their sides turned towards the notches, more or less com- 

 pressed. Rachis articulate or continuous. Florets three or 

 more. Glumes opposite, equal, bluntish, concave. Outer palea 



coriaceous, rounded on the back 

 or slightly keeled, awnless or awned, 

 with callus limited by a furrow at 

 the base. Inner palea minutely 

 ciliate on the ribs. Lodicules two, 

 swollen at the base. Stamens three, 

 filaments capillary ; anthers oblong, 

 cleft at each end, pendulous. 

 Ovary turbinate. Styles two, slen- 

 der, reflexed. Stigmas feathery. 

 Grain ovate, oblong, blunt at both 

 ends, hairy at apex, convex on 

 outer side, grooved on inner, falling 

 off at maturity with the palese and callus adherent to it. 

 Starch grains simple. Broader leaves twisted to the right. 



Species. A. repens, 56. A. caninum, $7. 



Agropyrum repens. 

 Floret. For Spikelet see p. 65. 



Hordeum. Spike stoutish. Spikelets in threes, in each 

 notch of the stem, stem jointed and breaking at the notches. 

 Florets one or with a rudiment of 

 a second. Glumes narrow, usually 

 subulate, pointed and ending in a 

 bristly awn. Outer palea with five 

 nerves ending in a strong awn. 

 Stamens three. Ovary turbinate. 

 Styles two, villous, reflexed. Stigmas 

 leathery. Grain oblong, swelling, 

 angular and pointed at each end, 

 apex hairy, marked with a longi- 

 tudinal groove, adherent to outer 

 palea. Starch grains simple. 



Hordeum murinum. 

 Species. H. Sylvaticiim, S2. Floret. For Spikelet see p. 105. 



H. pratense, 53. H. murinum, 54. H. maritimum, 55. 



