346 



IOWA ACADEMY OF SCIENCfE Vol. XXV, 1918 



DESCRIPTIONS OF VEGETATIVE ORGANS 

 Agropyron repens. Quack Grass* or Coucli Grass. Figure 121 

 Pale g-reen glaucous perennial, or sometinies a bright green, but 

 lacking the bluish green color of Agropyron Smithii. This species 

 had no resisting period when transferred to the greenhouse or 

 to the laboratory. Often only one culm grows from a node. The 

 rhizomes are vigorous, creeping, especially rad'.'itiu'.- from the 



Fig. 121 — Agropyron repens. Quack Grass. A, blade; B, sheath; C, 

 collar ; D, bud ; E, old rhizome ; F, node ; G, scale ; H, roots ; I, auricle ; 

 J, ligule ; K, terminal node and shoot. 



terminal node of the last year's growi;h, or from the base of the 

 old culms. The rhizomes are coarse, averaging one-third cm. in 

 diameter. Scales are hairy and conspicuous, in som^ specimens 

 reaching from one node to the other; nodes sre one to one and 

 a half cm. apart; buds arise at the nodes, the terminal node al- 

 ways budding, from which a new shoot makes its appearance. 



