GRAMINEAE (GRASS FAMILY) 



139 



4. S. palustris (Michx.) Scribn. Culms 6-10 dm. high; sheaths and leaves 

 glabrous, or lower sheaths sometimes pubescent ; leaves 8-12 cm. long, 8-6 min. 

 wide, scabrous ; panicles 10-20 cm. long, narrow ; spikelets 

 6-7 mm. long ; glumes similar, lanceolate, acute, subequal ; 

 lemmas lanceolate, the first acute or acuminate-pointed, awn- 

 less, rarely short-awned : the second bearing a slender divergent 

 awn below the acute or 2-toothed apex ; awn 4-5 mm. long. 

 ( Trisptum pennsylvanicum Man. ed. 6, not Avena pennsylvanica 

 L. ; T. palustre Trin.) Low grounds, Mass, to 111. and 

 southw. Var. FLExu6sA Scribn. Culms 4-6 dm. high; panicles 

 8-12 dm. long, open, the flexuous branches widely spreading at 

 least in floiver ; spikelets 4-5 mm. long, the first floret usually 

 awned. Del (Commons), Pa. (Heller). FIG. 118. 



118. S. pal., v. flex. 

 Spikelet x 3. 



119. K. cristata x 2%. 

 Spikelet. Lower part 



of lemma spread 



open. 



42. KOELERIA Pers. 



Spikelets 2-4-flowered ; rhachilla prolonged into a naked pedicel behind the 

 upper palea ; glumes unequal, slightly shorter than the florets, membranaceous, 

 acute, the first 1-nerved, the second 3-nerved ; lemma char- 

 taceous-membranaceous, the margins scarious, faintly 3-5- 

 nerved, acute or mucronate ; palea hyaline ; grain loosely 

 inclosed within the subrigid lemma, free. Tufted perennials 

 with narrow leaves and densely flowered terminal spike-like 

 panicles. (Named for Prof. G. L. Koeler, an early writer 

 on grasses.) 



1. K. cristata (L.) Pers. Culms erect, 3-6 dm. high, 

 leafy at the base ; sheaths retrorsely pubescent, at least the 

 lower ; blades flat or becoming involute ; panicle cylindrical, 

 4-15 cm. long, often interrupted at base, pale and shining ; 

 spikelets 4-5 rnm. long ; the glumes and lemmas scabrous. Dry soil, Ont. and 

 O. to B. C., and southw.; introduced in N. E. (Eurasia.) Very variable. 

 FIG. 119. 



43. TRISETUM Pers. 



Spikelets 2 (rarely 3-5) -flowered, rhachilla prolonged behind the upper palea 

 as a hairy bristle or pedicel ; glumes unequal, the second 

 about as long as the florets, keeled ; lemma membranaceous, 

 keeled, 2-toothed at the apex, bearing a slender dorsal awn 

 palea narrow, 2-toothed ; grain smooth, inclosed in the lemma 

 and palea but free from them. Tufted perennials with nar- 

 row or spike-like or loose terminal panicles. (Name from 

 tres, three, and seta, a bristle.) 



1. T. spicatum (L.) Richter. Culms slender, erect, 1.5-6 

 dm. high ; sheaths and blades more or less puberulent, blades 

 2-1 Ocm. long, 1-3 mm. wide ; panicle shining, spike-like, 3-12 

 cm. long, often interrupted below ; spikelets 5-6 mm. long ; 

 the second glume broader than the first, 3-nerved ; lemma 

 minutely scabrous, the awn inserted about $ below the acumi- 

 nate-toothed apex, 4-5 mm. long, divergent. ( T. subspicatum 

 Beauv. and var. molle Gray.) Mts. and rocky banks, Lab. m T - spicatum x3. 

 to Alaska, s. to Ct., N. Y., the Great Lakes; and along the Spikelet and floret, 

 mts. toN. C. (Eurasia.) FIG. 120. 



2. T. melicoides (Michx.) Vasey. Culm 3-8 dm. high ; 

 sheaths and blades roughish ; panicle shining, lax, nodding, 

 10-12 cm. long; spikelets 7 mm. long ; callus hairy ; lemma 

 minutely scabrous, bluntly 2-toothed at the apex, awn 1-2 

 mm. long, straight, erect. ( Graphephorum Desv. ) Gulf 

 of St. Lawrence to the Great Lakes, s. to N. B., Me., 

 121. T. mel., v. maj. x 2. and Vt. Var. MA.JUS (Gray) Hitchc. Lower sheaths 

 Spikelet and floret. pubescent ; upper surface of the leaves pilose ; lemmas 



