KEY TO COMMERCIAL SEEDS. 19 
KEY TO COMMERCIAL BLUEGRASS SEEDS AFTER PREPARATION FOR 
MARKET. 
Seeds 4-6 mm. long; web longer than glume, forming a woolly tuft and causing the 
SCOOSHORCLULOE Vita OWUISCILES: U1) CILCASCMIUD IC = see et ee se er P. arachnifera. 
Seeds 2-2? mm. long, usually rubbed free from hairs and disconnected in the sample, 
often more or less torn at the apex; commonest commercial kinds. 
Intermediate veins distinct; seeds contracted at the apex and not wider above than 
below the middle; hyaline margin of apex seldom present in rubbed seed. 
P. pratensis. 
Intermediate veins very indistinct; seeds broader above than below the middle; hyaline 
margin of apex usually evident and flaring ..-....--:--...--.---- P. compressa. 
Seeds 2-3 mm. long, chiefly unrubbed; disconnected or clinging somewhat in the 
sample; usually not torn at the apex; smooth or the pubescence on the veins 
and the web more or less evident. 
Intermediate veins indistinct. 
Rachilla segment usually pubescent; long, sterile racbilla segments conspicuously 
common; intermediate veins scarcely evident; keeland marginal veins pubescent; 
apex of seed often flaring; seed 23-3 mm. long ..-..--.-...-..- P. nemoralis. 
Rachilla segment smooth; intermediate veins but slightly evident; keel and marginal 
veins pubescent; apex of seed sometimes flaring; seed 2-23 mm. long. P. triflora. 
Intermediate veins very distinct. 
Rachilla segment smooth and slender; keel pubescent, marginal veins usually 
smooth; apex of seed acute and compressed; seeds often distinctly curved as 
VCUC On| ROM UILCESULE geen ea ees ee rhea nee Sa a= oe Bec arase Gaia P. trivialis. 
