POA PRATENSIS
6. Poa pratensis L. Kentucky Bluegrass, Junegrass.
A dark green leafy perennial with creeping rootstocks, forming a dense sod; common in pastures, meadows, roadsides and lawns, thriving best in good soils with a moderate amount of moisture.
Leaves folded in the bud-shoot. Sheath compressed but not sharply keeled, glabrous, green, closed when young but later split with margins sometimes overlapping. Auricles absent. Collar medium broad, usually ciliate, yellowish green, slightly divided by the midrib. Ligule membranous, very short (0.2 to 0.6 mm. long), truncate, entire to finely ciliate, puberulent on back. Blade 2 to 5 mm. wide, 5 to 40 cm. long, usually V-shaped, tightly folded in dry weather, keeled below, parallel-sided and abruptly narrowed to a boat-shaped tip, sometimes minutely pubescent, not ridged, deep green, sometimes shiny on under surface, not glaucous; margins scabrous; the row of motor cells on each side of the midrib shows as two light lines by transmitted light; the long blades forming almost right angles with the axis of the shoot.
Poa pratensis is distinguished from P. compressa by the deeper green colour of its foliage, by the longer, parallel-sided blades, which are sometimes puberulent towards the base, and by the shorter ligule.
This grass, when growing in dry situations, has its narrow blades closely folded and might easily be confused with Festuca rubra. The absence of ridges on the inner surface when the blade is unfolded will distinguish it.