GENUS 52. GRASS FAMILY. 217 



i. Trisetum spicatum (L.) Richter. Narrow False Oat. Fig. 523. 



Aira spicata L. Sp. PI. 64. I753- 

 Aira subspicata L. Syst. Veg. Ed. 10, 673. 1759. 

 Avena mollis Michx. Fl. Bor. Am. I : 72. 1803. 

 Trisetum subspicatum Beauv. Agrost. 180. 1812. 

 T. spicatum Richter, PI. Europ. i : 59. 1890. 



Softly pubescent or glabrous, culms 6'-2 tall, erect, 

 simple. Sheaths usually shorter than the internodes ; 

 ligule i"-i" long; blades i'-4' long, "-2" wide; panicle 

 spike-like, i'-s' in length, often interrupted below, its 

 branches i or less long, erect; spikelets 2-3-flowered, 

 the empty scales hispid on the keel, shining, the second 

 about 2i" long, the first shorter ; flowering scales 2"- 

 2\" long, acuminate, scabrous, each bearing a long bent 

 and somewhat twisted awn. 



In rocky places, Labrador to Alaska, south on the moun- 

 tains to North Carolina, New Mexico and California. Also 

 in Europe and Asia. Downy Oat-grass. Aug.-Sept. 



2. Trisetum flavescens (L.) Beauv. Yellow False Oat. Fig. 524. 



Avena flavescens L. Sp. PI. 809. 1753. 

 Trisetum pratense Pers. Syn. i : 97. 1805. 

 T. flavescens Beauv. Agrost. 88. 1812. 



Culms ij-2i tall, erect, simple, smooth and gla- 

 brous. Sheaths shorter than the internodes, more or 

 less pubescent; ligule i" long; blades i$'-s' long, 

 i "-3" wide, scabrous, sometimes sparingly hairy; 

 panicle open, 2.'-$' in length, the branches ascending 

 or erect, somewhat flexuous, naked below, the lower 

 i '-2' long; spikelets 3-4-flowered; empty scales 

 smooth and glabrous, the second acute, 2i" long, the 

 first about half as long, narrower, acuminate; flow- 

 ering scales 2i"-3" long, scabrous, bearing a long 

 bent and twisted awn. 



Introduced into Missouri and Kansas. Native of 

 Europe and Asia. Panicle yellow, turning dull brown. 

 Golden, Tall or Yellow Oat-grass. July-Aug. 



3. Trisetum pennsylvanicum (L.) Beauv. Marsh 

 False Oat or Oat-grass. Fig. 525. 



Avena pennsylvanica L. Sp. PI. 79. 1753. 



Avena palustris Michx. Fl. Bor. Am. i : 72. 1803. 



Trisetum pennsylvanicum Beauv.; R. & S. Syst. 2: 658. 1817. 



Trisetum palustre Torn Fl. U. S. i : 126. 1824. 



Culms i-3 tall, erect, simple, slender and often weak, 

 smooth and glabrous. Sheaths shorter than the internodes, 

 sometimes scabrous; ligule i" long; blades i'-6' long, 

 i "-3" wide, rough; panicle 2'-8' in length, yellowish, nar- 

 row, the branches ascending, the lower i'-2 f long; spike- 

 lets 2-flowered ; outer scales smooth, shining, subequal, the 

 second 2"-2$" long; flowering scales 2"-2i" long, scabrous, 

 the lower not long-awned, but a rudimentary awn some- 

 times present, the upper with a long bent and twisted awn. 



In swamps and wet meadows, Massachusetts to Illinois, south 

 to Florida and Louisiana. Ascends to 3500 ft. in Virginia. 

 Panicle sometimes loose and nodding. June-July. 



