THE GENERA OF BRITISH FLOWERING PLANTS 221 



compressed; glumes equal, boat-shaped, keeled, 6, 

 third and fourth imperfect, not awned; stamens 3. 



477. Anthoxanthum. Spikelets in spike-like 

 panicle, interrupted; glumes unequal, awned, 6, 

 third and fourth empty; stamens 2; paleae 

 leathery, unequal. 



478. Hierochloe. Spikelets in an open panicle; 

 upper floret perfect; 2 lower male, j-androus, 

 awnless; ovary smooth. 



479. Alopecurus. Spikelets in dense, cylindrical 

 spike, jointed on pedicel; glumes 6, awnless; 

 paleae awned, i -nerved. 



480. Milium. Panicle spreading; spikelets 

 stalked; rachilla not produced beyond flowering 

 glume; glumes equal; paleae awnless; flowering 

 glume hardening round fruit. 



481. Phleum. Spikelets in dense, cylindrical 

 spike, or panicle; flowering glume enclosing the 

 fruit; paleae awned, 2-nerved, glumes 3. 



482. Mibora (Knappia). Spike simple; spike- 

 lets dorsally compressed, solitary, one-sided, 

 i -flowered; glumes blunt; palea membranous, 

 shaggy, truncate, awnless. 



483. Agrostis. Spikelets in loose panicle; 

 flowering glume small, hyaline; glumes unequal, 

 upper smaller; outer paleae awnless. 



484. Polypogon. Spikelets in close contracted 

 spike-like panicle; glumes with long bristles, 

 membranous, lower palea awned from just below 

 tip. 



485. Calamagrostis. Panicle spreading; ra- 

 chilla with long silky hairs; glumes subequal; 

 lower palea awned. 



486. Deyeuxia. Panicle close, spike-like; 

 glumes equal; rachis ciliate, longer than flowering 

 glume; empty glumes large; flowering glumes 

 awned. 



487. Gastridium. Panicle close, spike-like; 

 rachilla produced beyond flowering glume; glumes 

 acute, awnless; empty glumes large, boat-shaped; 

 flowering glume small, 4-toothed. 



488. Apera. Panicle loose; glumes acute, awn- 

 less, unequal, lower smaller; outer paleae awned; 

 flowering glume 2-fid, awned; empty glumes 

 large. 



489. Ammophila. Spike cylindrical, large; 

 spikelets large; glumes subequal, lower shorter; 

 paleae hairy below ; rachilla long, silky. 



490. Lagurus. Spike ovate; glumes with long 

 bristles; empty glume plumose; flowering glume 

 3-awned; lower palea with 2 bristles and twisted 

 awn. 



491. Aira. Spikelets in loose panicle; rachilla 

 not produced beyond uppermost flowering glume; 

 awn dorsal, twisted, lower paleae 2-fid ; glumes 

 equalling lower floret. 



492. Corynephorus ( Weingcertneria). Florets 

 2, awned; awn straight, jointed, upper part club- 

 shaped, tuft of hairs at junction. 



493. Deschampsia. Florets 2; awn straight, 

 rachilla longer than upper flowering glume; lower 

 palea jagged. 



494. Holcus. Florets 2; lower perfect, awnless; 

 upper male, with dorsal awn ; paleae hardening 

 on fruit. 



495- Trisetum. Florets 2-6 in spikelet, crowded; 

 flowering glume 2-fid, awned; awn twisted; 

 ovary smooth; fruit not crested. 



496. Avena. Florets 2-6; glumes equalling 

 lower floret; awn dorsal, keeled, twisted; ovary 

 hairy above; fruit crested and furrowed. 



497. Arrhenatherum. Florets 2; upper perfect, 

 lower staminate only; rachilla produced beyond 

 flowering glumes; lower with awn long, twisted 

 from below middle; upper with short straight awn 

 near tip. 



498. Cynodon. Spikelets fingered in com - 

 pound, spreading spike; in 1-2 series; rachis 

 flat, laterally compressed; glumes equal, spread- 

 ing, awnless. 



499. Sieglingia ( Triodia). Spikelets 2- (or more) 

 flowered; rachilla not bearded; glumes unequal, 

 acute, as long as outer palea; flowering glume 

 deeply concave, notched, with teeth ; fruit free. 



500. Phragmites (Arundo). Spikelets with 2 

 or more perfect flowers; rachilla bearded, with 

 long silky hairs; fruit not attached to palea. 



501. Sesleria. Florets without awn; spikelets 

 in panicled spike, with ciliate bract below, over- 

 lapping; lower palea keeled, membranous; with 

 3-5 points. 



502. Cynosurus. Spikelets in spike or head; 

 bract below pectinate; glumes subequal, keeled; 

 lower palea with bristle; fruit enclosed in palea. 



503. Koeleria. Spikelets in sub-cylindrical in- 

 terrupted spike, 2- (or more) flowered, flattened; 

 flowering glume membranous; fruit not enclosed 

 in palea. 



504. Molinia. Panicle contracted, conical, 

 round in section, glumes shorter than florets, 

 without lateral ribs; florets 1-2; palea hardening 

 in fruit. 



505. Catabrosa. Panicle spreading, loose, 

 branches whorled; glumes unequal, i-veined; 

 florets 2, distant. 



506. Melica. Florets 1-2 perfect, rounded on 

 back, and i or more imperfect; glumes equal, 

 veined, nearly as long as spikelet ; palea harden- 

 ing in fruit. 



507. Dactylis. Panicle secund; spikelets 

 crowded, few; glumes unequal; lower keeled; 

 lower palea flattened; fruit free. 



508. Desmazeria. Spikelets 2-rowed, in spike, 

 rigid; glumes 8-12; blunt, blunt-pointed, with 

 faint nerves. 



509. Briza. Spikelets in panicle, drooping; 

 glumes broad, blunt, membranous, boat-shaped, 

 saccate; fruit attached to palea. 



510. Poa. Spikelets in panicle; glumes acute, 

 unequal; flowering glumes flat, keeled, awnless, 

 tips nerved. 



511. Glyceria. Spikelets with many flowers; 

 glumes unequal, membranous; flowering glumes 

 convex, tip blunt, nerveless; .lower palea with 

 7-10 ribs. 



512. Festuca. Panicle one-sided; flowering 

 glumes convex, tip nerved, acute, or awned; 

 ovary smooth; lower palea rounded or with ex- 

 current vein. 



513. Bromus. Spikelets in panicle; florets 



