Group XII. Ribless-bladed Grasses, with 

 Median Lines. 



Blade relatively thick, and hard or fleshy, therefore 

 dark-coloured when held up to the light. 

 Smooth-stalked Meadow Grass (Poa pratensis}. 



Fig. I. Rounded apex of blade. Observe the parallel 

 edges. 



Fig. 2. Rounded base of blade. 



Fig. 3. The extremely short ligule spread out and mag- 

 nified. The transverse line marks off the 

 ligule from the sheath. After Lund. 



Fig. 4. Transverse section of blade (magnified). Ob- 

 serve the relative thickness of the blade, and 

 the thin part on each side of the middle, cor- 

 responding to a median line. After Stebler, 



Fig. 5. Portion of blade as it appears by transmitted 

 light (magnified). The light band on each 

 side of the dark mid-rib is a median line. 

 The six black lines represent six veins, which 

 are seen (as white lines) by transmitted light. 



Blade soft and thin, therefore light-coloured when 

 held up to the light. 



Annual Meadow Grass (Poa annua}. Blade round- 

 pointed, often transversely wrinkled. 

 Fig. 6. Rounded apex of blade. Observe the edges, 



which are not parallel. 

 Fig. 7. Base of blade and ligule. The prominent blunt 



ligule suffices to identify this species. 

 Fig. 8. Transverse section of blade (magnified). Ob- 

 serve the relative thinness of the blade and the 

 median lines (the thin parts). After Lund. 

 Rough-stalked Meadow Grass (Poa trivialis}. Blade 

 tapered from the very base to the acute apex. 

 Always shining on lower surface. Acute keel 

 on sheath. 



Fig. 9. Acute apex of blade. 



Fig. 10. Portion of culm with long knot. Observe the 



base of a culm leaf with a long acute ligule ; 



the ligule of the radical leaf is short and blunt. 



Fig. II. Transverse section of blade (magnified). After 



Stebler. 



