362 



IOWA ACADEMY OF SCIENCE Vol. XXV. 1918 



dull, dark green, nerves prominent, one and one-half .to two mm, 

 broad, sharp pointed. Sheath somewhat lighter green than 

 blade, entirely enclosing bud, whitish to pale green near the 

 ground. Ligule narrow, indented at mid-nerve, membranous, 

 collar same color as sheath ; auricles wanting. 



Carex. Sedge. Figure 144. 



Rhizome thicker than in the grasses ; scales thick, coarse ; buds 

 very short ; ligule narrow, entire. 



Fig. 138.-Po« pnitensis. Kentucky Blue Grass, 

 shoot ; C, scales ; D, sheath. 



A, ligule ; B, terminal 



SUMMARY. 



1. Study was made of the vegetative organs of some peren- 

 nial grasses which were grown in the ST*eenhouse from October 

 until May. Resting periods were variable. 



2. Sporabolus longifolius, Muhlenbergia Mexicana, M. race 

 mosa, Spartina cynosuroides, Stipa spartea had resting peHods 



