330 WEEDS OF AGRICULTURE. 



SURFACE TWITCH (agrostis stohmfera august if alia). 

 Smaller-leaved Creeping-bent, or Spurious Fiorin, Red 

 Robin, &c. Panicle crowded with florets at the base 

 and towards the top; florets small; inner valve of the 

 calyx smooth, outer serrulated, corolla without any 

 rudiment of an awn. Perennial ; flowers in July and 

 August. 



COMMON KNOT-GRASS, or Wire-weed {poh/gomim 

 aviculare). Flowers axillary ; leaves elliptic-lanceolate, 

 rough-edged ; ribs of the stipulas distant ; stem pro- 

 cumbent, herbaceous. Annual ; flowers from April to 

 October. 



The root is fibrous, long, very tough, and somewhat 

 woody ; branched below ; stems many, spreading in every 

 direction, generally prostrate, much branched, round, striated, 

 leafy, with numerous knots or joints. This and the pre- 

 ceding are indifferently called surface twitch, or red robin, 

 by farmers ; on examination, one will be found a species of 

 the natural grasses, and the latter a species of buck-wheat. 

 They are mischievous weeds among broad-cast sown corn 

 and turnip crops, particularly in the early stages of the 

 growth of such crops. How to destroy these, is merely to 

 adopt the drill and row mode of culture, to keep the land 

 fertile by judicious manuring and cropping. Poverty of 

 soil and neglect of the hoe, or its imperfect use in the broad- 

 cast sowing mode of culture, are the great encouragers of 

 surface twitch. 



BLACK- GRASS {alopecurus agrestis), also called Black- 

 bent, Spear-grass, Slender Foxtail-grass, &,c. Culm 

 erect, roughish ; spike racemose, nearly simple, taper- 

 ing ; calyx glumes almost naked, combined at the base, 

 dilated at the keel. Annual ; flowers from July till 

 November. This annual and noxious species of foxtail- 

 grass is distinguished at first sight from the valuable 

 permanent pasture species, meadow-foxtail {alopeciirus 

 praiensis), by the want of woolly hairs on the spike, so 

 conspicuous in that of the a. prate/isis. 



