36 THE FLORA OF THE NOBTHEEN TEREITOEY. 



Spikes distant, at length spreading or re flexed. Spikelets alternate along 

 the rachis, but not close and appearing almost uniseriate. 



Leaves pubescent. Spikelets distant on a slender rachis. — 25. P. 



polyphyllum. 

 Leaves glabrous. Spikelets near together on a flattened rachis. — 

 9. P. distachyum. 



Series IV. Echinochloae. — Spikelets sessile and crowded in three or four 

 rows or irregularly along the simple alternate usually seound spikes or spike- 

 like branches of the panicle. Glumes sometimes awned. 



Spikelets about 1 line long, never awned, densely crowded in four rows 

 along the rachis, without hairs or bristles. — 6. P. colonum. 



Spikelets IJ to 2 lines long, acuminate or awned, crowded and clustered 

 along the rachis, usually intermixed with rigid hairs or bristles. — 6. P. Crus- 

 gaUi. 



Series V. Myuroideae. — Spikelets not silky, crowded and clustered in a 

 dense continuous or rarely interrupted cylindrical spike-like panicle. 



Spikelets ovoid, obtuse, J to | line long. — 20. P. myosuroides. 



Spikelets acuminate, curved, 1 to IJ lines long or rather more. — 25. P. 

 pihgerum. 



Series VI. Paniculatae. — Panicle branches usually more or less divided. 

 Spikelets all pedicellate (except sometimes first four species). Panicle branches 

 scarcely divided. ■ Spikelets few, rarely more numerous, scarcely under 2 lines 

 long. No male flowers. 



Spikelets nearly or sometimes quite sessile. — 11. P. foliosum. 

 Spikelets few, distinctly pedicellate in a loose spreading panicle. 



Spikelets 3 hues long, glabrous. Fruiting glume raised above the 

 others on a stipes dilated at the top. Panicle pedunculate. — 19. 

 P. majusculum. 

 Spikelets 2 lines long, glabrous. Fruiting glume raised above the 

 others. Panicle scarcely exceeding the floral leaves. — 24. P. 

 pauciflorum. 

 Panicle narrow or spreading. Spikelets numerous, 1 to near 2 hues long. 

 A male flower in the third glume. 

 • Spikelets crowded on the smaller branches. Glumes acute or acumi- 

 nate ; nerves of the second very prominent and rigidly ciliate. — 

 32. P. semitonsum. 

 Spikelets crowded or clustered on the smaller branches. Glumes 



acute or acuminate, not ciliate. — 1. P. antidotale. 

 Spikelets often numerous, shortly pedicellate not clustered. Glumes 



acute or acuminate. — 29. P. repens. 

 Spikelets numerous, on rather long pedicels. Glumes acute. — 4. P. 

 capilhpes. 

 Spikelets ^ to f Hne long. No male flower. — 35. P. trichoides. * 

 Spikelets usually numerous, 1 to near 2 lines long, pedicellate. No male 

 flower. — 3. P. Bunoei. 



Panicle spreading with numerous capillary branches. 



Lower panicle branches clustered but scarcely verticillate. — 8. P. 



deoompositum. 

 Lower panicle branches verticillate. Outer glume nearly as long as 

 the others. A palea in the third glume. — 34. P. trachyrhachis. 



1. P. antidotale, iJefe.— 160 miles N. of Camp IV., G. F. Hill (No. 428), 

 4/7/1911. 



