226 



POACEAE 



Spikelets not distinctly flattened and keeled. 

 Plants perennial. 



Creeping rhizomes present; lemmas glabrous, awnless or mucronate; panicle somewhat open, the 



branches ascending. 8. B. i)iennis. 



Creeping rhizomes absent (base of culm decumbent in B. laezipes). 

 Panicle narrow, the branches erect. 



Lemma glabrous or evenly scabrous. 9. B. erectus. 



Lemma appressed-pubescent on the margins and on the lower part. 10. B. suksdorfii. 



Panicle open, the branches spreading or drooping. 



Lemmas pubescent along the margin and on the lower part of the back, the upper dorsal part 

 glabrous. 

 First glume 3-nerved; plant pale or glaucous. 11. B. laevipes. 



First glume 1-nerved, or only faintly 3-nerved at base. 



Ligule prominent, 3-5 mm. long; lemmas narrow, the awn usually more than 5 mm. long. 



12. B. vulgaris. 

 Ligule inconspicuous, about 1 mm. long; lemmas broad, the awn 3-5 mm. long. 



13. B. richardsoni. 

 Lemmas pubescent rather evenly over the back. 



Branches of the panicle short, stiffly spreading; blades short, mostly on the lower part of 



the plant. 14. B. orcitttianus. 



Branches of panicle lax or drooping; blades elongate, scattered. 



Panicles small, nodding or drooping, usually not over 10 cm. long; spikelets densely and 



conspicuously pubescent; blades narrow, 2-4 mm. wide. 15. B. portcri. 



Panicles larger, erect, the branches more or less drooping; blades mostly wide and lax. 

 Blades pilose above, scabrous or smooth beneath; ligule 3-4 mm. long; panicle large 



and open, the slender branches long and drooping. 16. B. pacificus. 



Blades pubescent on both surfaces, but not pilose; ligule short. 



17. B. grandis. 

 Plants annual. 



Panicle contracted, usually dense, the branches erect or ascending. 

 Awn 5-8 mm. long. 

 Lemmas pubescent. 

 Lemmas glabrous. 

 Awn 15-20 mm. long. 



Culms pubescent below panicle. 

 Culms glabrous. 

 Panicle open, the branches spreading. 



Awn short or wanting; lemmas broad, obtuse, inflated. 

 Awn well developed. 



Awn twisted and bent. 



Awn not twisted and bent (sometimes curved or divaricate). 

 Sheaths smooth. 

 Sheaths pubescent. 



Lemma narrow, gradually acuminate;- awn 1-5 cm. long. 



Second glume usually less than 1 cm. long; pedicels capillary, flexuous. 



25. B. tectorum. 

 Second glume more than 1 cm. long; pedicels sometimes flexuous but not capillary; 

 spikelets scabrous. 

 Awn about 2 cm. long; first glume about 8 mm. long. 26. B. sterilis. 



Awn 3-5 cm. long; first glume about 15 mm. long. 27. B. rigidus. 



Lemma broad, abruptly narrowed above. 



Branches of panicle rather stiffly spreading or drooping, not flexuous; awn straight. 



28. B. commutatus. 

 Branches slender and flexuous. 



Lemmas pubescent; awn straight. 29. B. arenaruts. 



Lemmas glabrous; awn becoming divergent. 30. B. japomcus. 



18. B. hordcaceiis. 



19. B. raceinosus. 



20. B. rubens. 



21. B. madritensis. 



22. B. brisaeformis. 



23. B. trinii. 



24. B. secalinus. 



1. Bromus unioloides H. B. K. 



Rescue Grass. 



Fig. 



530. 



Bromus nnioloidcs H. B. K. Nov. Gen. & Sp. 1: 151. 



1816. 

 Ccratochloa haenkeanus Presl, Rel. Haenk. 1: 285. 



1830. 

 Bromus haenkeanus Kunth, Rev. Gram. 1: Suppl. 



XXXIL 1830. 

 Bromus schraderi Kunth, Enum. PI. I: 416. 1833. 

 Ccratochloa brcviaristata Hook. Fl. Bor. Am. 2: 253. 



pi. 234. 1840. 

 Bromus nnioloidcs haenkeanus Shear, U. S. Dept. Agr. 



Div. Agrost. Bull. 23: 52. /. 31. 1900. 



Annual ; culms 60-100 cm. tall ; sheaths pilose ; 

 blades narrow, very scabrous ; panicle open or 

 sometimes reduced and narrow ; spikelets about 

 2.5 cm. long, 5-9 mm. broad ; glumes smooth, 

 the first 5-nerved, 7-10 mm. long; the second 

 7-nerved, 10-12 mm. long; lemmas acute, sub- 

 coriaceous, glabrous or scabrous, 12-16 mm. 

 long ; awn 2 mm. long or less ; palea half to 

 three-fourths as long as the lemma. 



Native country not certainly known, but probably 

 the Andes; now distributed from Chile to southern 

 United States. Introduced in southern and central 

 California. Apr.-June. 



