288 American Midland Naturalist Monograph No. 7 



17. Perianth 3-4 mm long, the segments acuminate; 

 heads 5- to 50-flowered; wet ground, locally 

 throughout 111. Aug. -Oct. /. canadensis J-Gay 



17. Perianth 2-2.5 mm long, the segments obtuse; heads 



3- to 5-flowerecl; wet ground in the northern and 



centi'al counties. July-Sept 



/. brachycephalus (Engelm.) Buch. 



16. Seeds not caudate; perianth-segments acuminate. 



18. Capsule twice as long as the perianth; wet ditches, 



rare; Jackson Co /. diffusissimus Buckl. 



18. Capsule equalling to one-third longer than the 



perianth. 



19. Capsule acuminate or subulate, longer than the 



perianth; heads 2-30, each 15- to 40-flowered; 



perianth 2.5-3 mm long; wet sandy soil in the 



northern half of 111. July-Sept 



/. scirpoides Lam. 



19. Capsule obtuse or merely acute at the apex, 



about equalling or shorter than the perianth. 



20. Capsule about two-thirds the length of the 



perianth; sepals longer than the petals; wet 



ground. June-Aug 



/. hrachycarpus Engelm. 



20. Capsule about equalling the perianth; sepals 

 and petals nearly equal. 

 21. Heads 1-50; branches of the inflorescence 

 ascending; perianth 3-3.5 mm long; wet 



ground, throughout 111. May-Aug 



/. acuniinatus Michx. 



21. Heads more numerous; branches of the 

 inflorescence widely divergent; perianth 

 2-2.5 mm long; swampy ground, not 

 common. June-July. [/. robustus sensu 

 auth., non Wats.] /. nodatus Coville 



2. Luzula DC. — Woodrush 



1. Flowers solitary (rarely 2) at the tips of the slender ascending or 

 loosely spreading peduncles; inflorescence an umbel; perianth 

 3-4.5 mm long, pale brown, shorter than the capsule; wooded 

 banks, rare; La Salle and Ogle counties. [L. acuminata Raf. 



( ?) ] L. saltuensis Fern. 



1. Flowers subsessile, crowded in small head-like clusters. 



2. Rays of the inflorescence erect or ascending; perianth 2-3 mm 



long; heads mostly cylindrical. 



3. Base of plant commonly with small corms; perianth about 



2.5 mm long, slightly shorter than the capsule; stem-leaves 



2-4 mm wide; sandy soil in open woods, local. Apr.-May 



L. hulbosa (Wood) Rydb. 



