GRAMINEAE 27 



2. C. inexpansa A. Gray. lA°-3° high, stout : panicle long, its 

 branches short and erect : spikelets straw-colored, \\"-2" long, the basal 

 hairs about the length of the third glume : awn slightly bent, about the 

 length of the glume. — Of rare occurrence in low woods along the Missouri 

 Elver near Courtney. June-July. 



25. CALAMOVILFA Hack. 



The rachilla not produced, the outer glumes unequal, and the third 

 glume not awued. Otherwise much as in Calamagrostis. 



1. C. longifolia (Hook.) Hack. Reed-grass. Glabrous perennial 

 with long creeping rootstocks, 4°-6° high : panicle 10' long, narrow, 

 interrupted at base, its branches erect : spikelets 2.j'''-3'' long. — In one 

 locality in the sandy Missouri River bottom near Atherton ; also near 

 Harlem, Clay County, Missouri. August. 



26. APERA Adans. 



An annual with one-flowered spikelets in an open panicle. Rachilla 

 produced beyond the flower in the form of a bristle. Flowers much as in 

 Agroslis, but the third glume two-toothed and bearing a long slender awn. 

 Palet a little shorter, two-toothed. 



1. A. Spica-venti (L.) Beauv. Bent-grass. 1°-2° tall, withapan- 

 icle4'-8' long, its branches capillary : spikelets \'^-\Y' long, the delicate 

 awn 3''-4'' long. — Very sparingly adventized along the railroad from 

 Courtney to Sheffield. June-July. 



27. HOLCUS L. 



Spikelets 2-flowered in close panicles. Glumes four, the two lower 

 empty, the first and second three-nerved, the third awnless, enrlosing a 

 perfect flower, the fourth bearing a short bent awn and enclosing a stam- 

 inate flower. 



1. H. lanatus L. Velvet-gkass. A softly pubescent annual, l2°-2i° 

 high : panicle dense, 2^-3' long : spikelets 2" long.— Rarely occurs as a 

 waif along railroads at Shefiield. July. 



28. TRISETUM Pers. 



Perennials with 2-4-flowered spikelets in open panicles. Two lower 

 glumes empty, the flowering two-toothed and bearing a short bent or 

 flexuous awn below the apex. Palet two-toothed. Rachilla extending 

 beyond the flowers. 



1. T. flavescens (L.) R. & S. False Oats. 11° -21° high, smooth : 



panicles 2'-5' long, yellowish, open, the branches naked below : spikelets 



3-4 flowered. — Sparingly adventized along railroads from Courtney to 



Sheffield. July-August. 



29. AVENA L. 



Lower flowers perfect, upper imperfect. Two lower scales large, empty, 

 membranous and persistent. Flowering glumes firmer in texture, two- 

 toothed. Palet narrow. 



