5. Ammophila arenaria (L.) Link BB. Floret without hairs at the base; nerve of lemma not silky, caryopsis at maturity falling from the palea and lemma; seed loose in pericarp, this opening when ripe - lemma 1-nerved Sporobolus Plants perennial A. Plants producing creeping rhizomes; panicle narrow or spike-like S. virginicus (L.) Knuth AA. Plants not producing a creeping rhizome glumes nearly equal, much shorter than lemma, panicle narrow and spike-like, panicle branches short and appressed S. poiretii (R and S.) Hitch. Tribe II. Festucae Spikelets all alike in the same inflorescence. A. Lemmas three nerved, nerves prominent, often hairy Inflorescence an exerted open or spike-like panicle Lemmas not pubescent on the nerves, awless, glumes shorter than the lemmas; lateral nerves of the lemmas not marginal internerves globious. Lemmas membranaceous; spikelets compressed; lemmas acute or acuminate; spikelets 3 to many flowered Fragrostis AA. Lemmas 5 to many nerved, the nerves sometimes obscure Spikelets with no empty lemmas below the fertile florets, nerves usually prominent; lemmas membranaceous Glumes present, lemmas longer than broad, keeled on the back, awless; spikelets small Poa