GENUS 82. 



GRASS FAMILY. 



245 



82. KOELERIA Pers. Syn. i : 97. 1805. 



Tufted annual or perennial grasses, with flat or setaceous leaf-blades and mostly spike- 

 like panicles. Spikelets 2-5-flowered. Two lower scales empty, narrow, acute, unequal, 

 keeled, scarious on the margins; the flowering scales 3~5-nerved. Palet hyaline, acute, 

 2-keeled. Stamens 3. Styles very short. Stigmas plumose. Grain free, enclosed in the 

 scale and palet. [In honor of Georg Ludwig Koeler, German botanist.] 



About 15 species of wide geographic distribution. The following, which may contain two forms, 

 occurs in North America. Type species : Poa nitida Lam. 



i. Koeleria cristata (L.) Pers. Koeler's- 

 grass. Crested Hair-grass. Fig. 589. 



Aira cristata L. Sp. PI. 63. 1753. 



Koeleria cristata Pers. Syn. I : 97. 1805. 



Koeleria nitida Nutt. Gen. I : 74. 1818. 



Koeleria cristata van gracilis A. Gray, Man. 591. 1848. 



Culms i-2j tall, erect, simple, rigid, smooth, 

 often pubescent just below the panicle. Sheaths 

 often shorter than the internodes, smooth or sca- 

 brous, sometimes hirsute; ligule i" long; blades 

 i'-i2' long, V-\\" wide, erect, flat or involute, 

 smooth or rough, often more or less hirsute; panicle 

 i '-7' in length, pale green, usually contracted or 

 spike-like, the branches erect or rarely ascending, i' 

 long or less ; spikelets 2-5-flowered, 2"-$" long, the 

 scales rough, acute, the empty ones unequal; flower- 

 ing scales iJ"-2" long, shining. 



In dry sandy soil, especially on prairies, Ontario to 

 British Columbia, south to Pennsylvania, Texas and Cali- 

 fornia. Also in Europe and Asia. Very variable. Prairie 

 June-grass. July-Sept. 



83. CATABROSA Beauv. Agrost. 97. pi. 19. f. 8. 1812. 



A perennial grass, with soft flat leaf-blades and an open panicle. Spikelets usually 

 2-flowered. Two lower scales empty, thin-membranous, much shorter than the flowering 

 ones, unequal, rounded or obtuse at the apex; flowering scales membranous, erose-truncate. 

 Palet barely shorter than the scale. Stamens 3. Styles distinct. Stigmas plumose. [Greek, 

 in allusion to the erose top of the flowering scales.] 



A monotypic genus of arctic and mountainous regions of the northern hemisphere. Type 

 species : Aira aquatica L. 



i. Catabrosa aquatica (L.) Beauv. Water 

 Whorl-grass. Fig. 590. 



Aira aquatica L. Sp. PI. 64. 1753. 

 Catabrosa aquatica Beauv. Agrost. 157. 1812. 



Smooth and glabrous, culms 4'-2 tall, erect, from 

 a creeping base, bright green, flaccid. Sheaths usu- 

 ally overlapping, loose; ligule ii"-2i" long; blades 

 ii'-5' long, i "-3" wide, flat, obtuse; panicle i'-8' 

 in length, open, the branches whorled, spreading or 

 ascending, very slender, i'-2' long; spikelets ii"-if" 

 long, the empty scales rounded or obtuse, the first 

 about half as long as the second, which is crenulate 

 on the margins; flowering scales i"-ij" long, 

 3-nerved, erose-truncate at the apex. 



In water or wet soil, Labrador and Newfoundland to 

 Alaska, south to Nova Scotia, Nebraska and Colorado. 

 Also in Europe and Asia. Water-grass, Water Hair- 

 grass. Summer. 



