Hifclicock — The Grasses of Hazcaii 143 



1. Avena sativa L. Sp. PI. jg. 1753. Cultivated oat. 



Similar to A. fatiia: florets not readily separating from the glumes, spikelets commonly 

 2-flo\vered : lemma glabrous : awn straight, or wanting. 



Occasional in waste places, mostly as a waif. Originally described from 

 cultivated plants in Europe. 

 Oahu : Schofield Barracks. Hitchcock 13972. 



2. Avena fatua L. Sp. PI. 80. 1753. Wjld oat. 



Plants annual : culms 30 to 90 cm. tall, erect, stout : panicle loose and open, the slender 

 liranches as a rule horizontally spreading: spikelets commonly 3-flo\vered : glumes about 2.5 cm. 

 long: rachilla and lower part of shining lemma clothed with long stiff brownish hairs; florets 

 readily falling from the glumes : lemma nerved above, about 2 cm. long, the teeth acuminate but 

 not awned : awn stout, geniculate, red-brown, twisted below, about 3 cm. long (fig. 28). 



^^'eed along roadside; introduced. Originally described from Europe. 

 Oahu: Nuuanu Pali, Hitchcock 13749. 



3. Avena barbata Brot. Fl. Lusit. i :io8. 1804. 



Differs from A. fatua in having somewhat smaller, 2-flowered spikelets, with curved and 

 capillarv pedicels : teeth of lemma ending in fine awns 2 mm. long. 



^^^eed along road; introduced. Originally described from Europe. 

 Oahu: Schofield Barracks, Hitchcock 13934- 



14. ARRHENATHERUM Beauv. 



Spikelets 2-flowered. the lower floret staminate, the upper perfect, the rachilla disarticu- 

 lating above the glumes, produced bej'ond the florets as a slender bristle : glumes rather broad 

 and papery, the first i-nerved, the second a little longer than the first and about as long as the 

 spikelet. 3-nerved : lemmas 5-nerved, hairy on the callus, the lower bearing near the base a 

 twisted, geniculate, exserted awn, the upper bearing a short straight, slender awn just below 

 the tip. Perennial, rather tall grasses, with flat blades and rather dense panicles. 



1. Arrhenatherum elatius (L.) Beauv. : Mert. & Koch in Rohl. Deutsch. Fl. i :S46. 1823. Tall 



MEADOW OAT GRASS. 



Avena elatior L. Sp. PI. 79. 1753. 



Arrhenatherum avenaccuni Beauv. Ess. Agrost. 152. pi. 11. f. 5. 1812. 



Culms a meter or more tall : blades as much as i cm. wide, scabrous on both surfaces : 

 panicle pale or purplish, shining-, 15 to 30 cm. long, narrow, the short branches verticillate, usuallv 

 spikelet-bearing from the base : spikelets 7 to 8 mm. long : glumes minutely scabrous, the second 

 about equaling the florets : lemmas scabrous, the awn of the staminate floret about twice the 

 length of its lemma: palea as long as the lemma (fig. 29). 



Pasture land at medium altitudes. Cultivated as a pasture grass and estab- 

 lished here and there. Originally described from Europe. 

 Hawaii: Kukaiau Raiich, Hitchcock 14267. 



15. AIR A L. 



Spikelets 2-flowered, disarticulating above the glumes, the hairy rachilla prolonged behind 

 the upper floret as a stipe, this in some plants bearing a reduced floret : glumes about equal, 

 acute or acutish, membranaceous; lemmas thin, truncate and 2 to 4-toothed at the summit, bear- 

 ing a slender awn from or below the middle, the awn straight, bent or twisted. Low or moder- 

 ately tall annual or common!)- perennial grasses, with shining pale or purplish spikelets in narrow 

 or open panicles. 



[45] 



