448 Key to the System of 



AFHELXA. 



1907. Floral bracts narrowly membranous at the margin. 



Very dwarf ; leaves often shorter than the stem ; spikelet 

 compressed, mostly reclining ; bracts often beset with 

 minute hairlets, the lowest much longer than the next 

 and only that one pointed ; flowers mostly unisexual, 

 reduced to a single stamen or single pistil, stamen besides 

 supported by a colorless pellucid inner bract or sepal ; 

 anther narrow ; stigma hardly broader than the style ; 

 fruit almost ellipsoid. A. gracilis. 



Floral bracts broadly membranous at the margin. 



Extremely dwarf; leaves almost as long as the stem; spike- 

 let mostly erect, much compressed, broadish, beset with 

 short hairlets ; the lowest bract hardly longer than the 

 next, all bracts pointed ; stamens and pistils each clasped 

 by an inner colorless sepalaceous bract and externally 

 supported by as many floral bracts ; stigma narrow ; fruit 

 almost ellipsoid. A. pumilio. 



CENTROLEFIS. 



1908. Glabrous ... ... 1909 



Beset with hairlets 1911 



1909. Spikelet very narrow. 



Quite minute, somewhat rigid, sometimes of a reddish tinge, 

 resembling a branchless slender moss ; leaves almost setu- 

 lar; outer floral leaf bract-like and often somewhat 

 recurved in its upper portion ; spikelet containing several 

 or many or even very numerous flowers, only the lowest 

 staminate ; pistils extensively coherent or connate, each 

 representing a flower or regardable as component parts 

 of a single flower ; fruits very minute. C. polygyna. 



Spikelet rather broad ... 1910 



1910. Floral leaves abbreviated. 



Minute ; leaves almost capillary ; floral leaves bract-like, 

 capillary-pointed, thus almost awned ; spikelet contain- 

 ing several flowers, only the lowest staminate ; stigma very 

 narrow, elongated ; base of fruit stalk-like. C. glabra. 



Floral leaves elongated. 



Stems compressed ; leaves narrow-linear, rather firm ; floral 

 leaves two, similar to the others but shorter, particularly 

 the second ; spikelet containing several or many flowers ; 



