WEEDS OF ARABLE LAND 131 



smooth, with a spreading branched panicle 3 to 5 inches 

 long, bearing oblong, smooth spikelets } to } inch long, 

 containing five to ten awned flowers. Flowering and 

 seeding occur in June to July or August ; the seeds may 

 lie dormant in the soil for several years, and as they 

 require considerable moisture to enable them to ger- 

 minate, they often spring up unexpectedly in damp 

 seasons. The seed is also present as an impurity in 

 cereal and grass seed samples ; care should therefore 

 be taken to sow only pure seed. 



The seeds may germinate in spring or autumn, at 

 which times an opportunity is offered to destroy the 

 young plants by ploughing under, or by harrowing 

 them out should dry, hot weather follow. 



Smooth Brome Grass (B. racemosus L.) and Field 

 Brome Grass (B. arvensis L.) may similarly be trouble- 

 some in corn crops. 



Bulbous Oat Grass (Arrhenatherum avenaceum Beauv., 

 var. bulbosum Lindl.), also termed Onion Couch, Knot 

 Oat-grass or Pearl-grass, is a variety of Tall Oat Grass 

 met with locally in different parts of the country. It 

 is often extremely harmful in arable land, and especi- 

 ally in cornfields. The inflorescence is a panicle 6 to 12 

 inches long, with nearly erect roughish branches, and 

 pale shining spikelets about the size and appearance of 

 those of a small oat, the flowering glume bearing a 

 dark, twisted, bent awn. The rootstock creeps a little, 

 and is tuberous at the nodes, several " bulbs," " pearls," 

 or " knots " occurring together like large beads on a 

 string, each " bulb " sufficing, if detached, to produce 

 a new plant. In addition, flowering occurs in June 

 and July, or later, and the tall stems growing among 

 corn crops readily scatter an abundance of seed, the 

 sowing of which it is impossible wholly to prevent. 

 As the " seeds" may be widely scattered at harvest 



