64 GRAMINEAE. 25. Aristida. 



25. ARISTIDA, L. 



(Latin arista, an awn : alluding to the trifid awn ) 

 Spikelets 1 -flowered, paniculate ; outer glumes 2, narrow, keeled, persistant ; flowering 

 glume rigid, mounted on a short callus and terminating in a 3 -fid awn ; palea small ; 

 hilum linear. Glabrous erect perennial tussock grasses, with subulate leaves, the panicle- 

 branches bearing very few spikelets. Often known as Wire-grasses. 



A. Awn with a long undivided basal part, which is spirally 



twisted and articulate on the glume. 



Undivided part about 3J cm. long A. stipoides 1. 



Undivided part about 1| cm. long A. arenaria 2. 



, A. Awn divided to the glume into 3 branches. 



B. Panicle short, broad and dense ; 2 outer glumes very 



unequal A. Behriana 3. 



B. Panicle narrow, compact or rather loose ; outer 



glumes nearly equal. 



Flowering glume about 6 mm. long A. ramosa 4. 



Flowering glume about 9 mm. long A. calycina 5. 



1. A. stipoides, R. Br. Panicle narrow, with erect branches ; lowest glume 10 mm. 

 long ; 2nd glume nearly double as long ; awn below the branches about 3£ cm. long ; 

 branches capiliary, 4-5^ cm. long. 



Far North. Sept. -Nov. 



2. A. arenaria, Gaudich. Mulga Grass. Shorter than the preceding with ascending 

 slender stems ; panicle narrow, often reduced to a raceme, purplish ; outer glumes as in 

 the preceding, but less rigid ; awn below the branches lJ-2^ cm. long ; branches usually 

 4-5^ cm. long. 



Central and Murray districts ; Far North and North- West. June-Nov. 



3. A. Behriana, F. v. M. A short ascending grass with thick rootstock and loose leaf- 

 sheaths, the uppermost blade sometimes as long as the panicle ; panicle only 5-8 cm. long, 

 dense and broad, purplish ; lowest glume 7-9 mm. long, the 2nd 14-18 mm. long ; flowering 

 glume 8-10 mm. long, with 3 capillary sessile awns, 3-4 cm. long. 



From Adelaide northwards to the Flinders Range ; Murray Lands. Sept. -Dec. 

 Usually in moist ground. 



4. A. ramosa, R. Br. Panicle narrow, 6-12 cm. long, with erect branches ; lowest 

 glume 5-6 mm. long, 2nd a little longer ; flowering glume 5-6 mm. long, with a very short 

 callus ; awns sessile, spreading, 8-14 mm. long. 



Flinders Range ; Far North. Aug. -Oct. 



5. A. calycina, R. Br. Very like the preceding, but the lowest glume is 7-8 mm. long 

 and the 2nd is 8-10 mm. and equals or slightly exceeds the flowering glume which is 

 about 9 mm. long and is sometimes slightly twisted above the part containing the grain ; 

 awns continuous with the flowering glume, 15-35 mm. long ; panicle to 20 cm. long. 



Flinders Range ; Far North and North-West. May-Jan. — Both these species are very 

 near A. Adscensionis, L. (A depressa, Retz.), and should perhaps be united with it as 

 varieties. 



26. STIPA, L. 

 Greek stype tow : alluding to the fibre obtained from Esparto Grass (S. tenacissima, L.) 



Spikelets 1 -flowered, usually paniculate ; outer glumes 2, membranous, keeled, per- 

 sistant, often turning purplish ; flowering glume usually shorter, convolute, finally 

 hardened, mounted on a short hairy callus, with a long terminal awn, which is kneed and 

 spirally twisted below the knee ; palea enclosed in the flowering glume ; anthers usually 

 tipped with bristles ; lodicules fleshy, oblong ; grain fusiform ; hilum linear. Perennial 

 grasses ; the leaves inrolled, at least when dry. 



Spear-grass, Corkscrew -grass. Injurious, when ripe, to sheep, owing to the sharp, 

 penetrating callus of the fruiting glume. 

 A. Flowering glume glabrous or nearly so. 



Panicle -branches feathery with long hairs 8. elegantissima 1. 



Panicle-branches with short hairs 8. Tuckeri 2. 



A. Flowering glume silky-hairy. 



B. Ligule glabrous, often long. 



C. Flowering glume shortly bilobed at summit. 



Leaves long ; spikelets in a panicle S. teretifolia 3. 



Leaves almost absent ; spikelets in a short raceme 8. Muelleri 4. 

 Flowering glume entire at summit. 



D Leaves nrolled- filiform ; stems slender 8. setacea 5. 



D Lower leaves flat, ribbed. 



Stems tall, stout S. acrociliata 6 



Stems short, wiry S. scelerata 7 



