﻿Nash : Genus Syxtherisma in North America 



^93 



Second scale one-half or less as long as the spikelet, 



rounded or truncate at the apex. 

 Second scale more than one-half as long as the 

 spikelet, sparingly pilose at the acute apex. 

 Hairs on the sheaths widely spreading ; nodes numerous. 

 Rachis of the racemes with the lateral angles broadly winged, thus 



making it appear flat ; first scale usually present, generally 

 wanting in Nos. 7 and 8. 

 Pedicels terete or sometimes obscurely angled, sparingly if at 



all hispidulous. 

 Sheaths and leaves strongly papillose-hirsute ; rachis of 

 the racemes .8 mm. or less wide; second scale one- 

 half or less as long as the spikelet. 

 Sheaths and leaves glabrous ; rachis of the racemes I 

 mm. or more wide ; second scale nearly as long as 

 the spikelet. 

 Pedicels sharply 3-angled, the angles strongly hispidulous. 

 Sheaths strongly papillose- hirsute ; racemes commonly 



more than 3. 

 Racemes very slender, the rachis usually less than 

 .5 mm. wide ; spikelets one-fifth as wide as 

 long, acuminate ; fourth scale greenish when ma- 

 ture. 

 Racemes stouter, the rachis usually exceeding .7 mm. 



wide ; spikelets one-quarter or more as 

 wide as long, acute ; fourth scale yellowish 

 white when mature. 

 Spikelets usually less than 3 mm. long, the 

 second scale one-half or less as long as the 

 spikelet, the third scale with the first and 

 second nerves on each side hispid above the 



4. 



S. graalhma. 



5. 



S. Bakeri. 



6. 



S. Simps oni. 



7. 6*. scroti mi 



8. S. linearis. 



9 



S. setosa. 



middle. 

 Spikelets commonly more than 3 mm. Ion 



10. S. san (in a lis 



g, the 



second scale more than one- half as long a 

 the spikelet, the third scale with the nerves 



smooth. 



Sheaths glabrous or nearly so ; spikelets about 4 mm. 

 long ; racemes 2. 



11. S. fun '■ 



12. S. barbata. 



*■ Syxtherisma filiformis (L.) Nash, Bull. Torr. Bot. Club, 



22 : 420. 



1895. 



filifi 



1753. 



Culms 1.5-7 dm. tall, slender, erect, simple or somewhat 

 branched, smooth and glabrous, more or less flattened ; nod< 2-4 



culm leaves 2-4 ; sheaths flattened, keeled, at least toward tin 



5 ex < papillose-hirsute, or the uppermost one glabrous, at Least 



*»mil«>f*lu tnnthrd Y\IVJ 1-2 ITim. 1 Oil LT \ 



ab 



e ; li 



ul 



e a scarious irregularly toothed iWj 



