AGROSTIS TENUIS
36. Agrostis tenuis Sibth. BROWN-TOP, COLONIAL BENT-GRASS, RHODE ISLAND BENT-GRASS.
A dark green, glabrous perennial spreading by short rootstocks, forming a compact sod or appearing slightly tufted; found in meadows and permanent pastures in the southern and eastern parts of our range on poor soils of moderate or small amount of moisture.
Leaves rolled in the bud-shoot. Sheath not compressed, glabrous, green or purplish, longer than internode on vegetative shoots, split with the hyaline margins overlapping. Auricles absent. Collar distinct, narrow, glabrous, light green, continuous or divided by the midrib, oblique. Ligule membranous, short (0.3 to 1.2 mm. long), truncate, entire or finely toothed, sparsely and minutely hairy on back. Blade 1.5 to 3.5 mm. wide, 2 to 10 cm. long, truncate at base, sharp-pointed, flat with margins rolling in towards the apex, involute in dry weather, dark green, dull or sometimes shiny on the under surface, distinctly ridged on the upper surface, slightly keeled on under surface; margins and upper surface scabrous.
A. tenuis can be distinguished from A. alba by its short, truncate ligule, smaller size and darker and more delicate foliage.
