96 CATABROSA.—- AIRA. [class hi. ORDER il, 



GENUS XXVI. CATABRO'SA. Beauvis. Whorl-grass. 



Gen. Char. Panicle loose. Spikelets two or three-flowered, some- 

 times with a fourtli imperfect floret. Glumes unequal, membra- 

 nous, obtuse, much shorter than the florets. Glnmelles nearly 

 equal, ribbed, awnless, the extremity truncated, erose. — Name 

 from Ko.rx'e^ua-ii;, a c/nawing ; because of the erose extremity of 

 the valves of the glumelles. 



1. C. aquat'ica, Beanv. (Fig. 120.) Water Whorl-grass. Panicle 

 with whorled spreading branches ; leaves broadly linear, flat, ob- 

 tuse. 



Lindley, Synopsis, p. 306. — Hooker, British Flora, vol. i. p. 39. — 

 Air'aaquat'ica, Linn. Englit^h Botany, t. 1557. — English Flora, vol. i. 

 p. 102. — Sinclair, Hort. Gram. Woburn. p. 351. 



Root of long white whirled fibres. Floating stems frequently long 

 and numerous. Floivering stems bent and branched at the base, 

 and rising from twelve to eighteen inches above the water, leafy, 

 smooth and striated. Leaves linear, short, broad, flat, obtuse, smooth, 

 striated, of^en floating on the surface of the water, a deep pleasant 

 green. Sheaths loose, smooth, striated. Ligula broad acute. /«- 

 Jlorescence a loose branched panicle, erect, large smooth. Glumes verj'' 

 unequal, thin, smooth, pui-plish, ribbed, the obtuse outer valve irre- 

 gularly notched, the inner about half as long. Florets much longer 

 than the glumes, the upper ones on short stalks (pedunculated), the 

 Talves equal, brownish green, a thickish texture, with strong greeu 

 ribs, white and membranous, at the blunt erose extremity. Anthers 

 yellow. Stigmas short, feathery. Seed small pale. 



Habitat. — Drains, pools and on the banks of rivers. 



Perennial flowering in May and June. 



A very variable plant in size, it has been found with decumbent 

 stems, by Mr. Neill, near Edinburgh, "about two yards in length," 

 and Mr. Wilson, " finds in the wet sand of the north shore at Liverpool 

 a variety not two inches high, each calyx (gluma) containing in 

 general but one perfect floret." It will not long flourish, except in 

 a wet muddy situation, consequently it is one that cannot be applied 

 to any agricultural purpose. 



GENUS XXVII. AFRA. Linn. Hair-grass. 



Ge\. Char. Panicle loose or close. Spikelets two flowered. 

 Glumes unequal. Glumelles unequal, the euler valve mostly 

 awned near the base. Fruit free. Name from cc^^u, tares, darnel, 

 a name anciently ap])lii'd by the Greeks to the Lolium temulentum, 

 and signifying dangerous or deadly ; but that is a plant rery dif- 



