28 THE TLORA OF THE NORTHERN TERRITORY. 



Spikelets both 2- flowered and awned. Outer glume rigid. Spikes 2 to 3, 

 rarely 4, erect, often appressed so as to appear like 1 cylindrical spike. Nodes 

 glabrous. Stem tall, erect. — 1. I. arundinaceum. 



Nodes bearded. Stems 2 to 3 ft. high. Awn exserted. — 2. I. australe. 



Sessile spikelet 2- flowered, awned. Pedicellate spikelet unawned, with a 

 male or without any flower. Spikes 2. — 3. I. decumbens. 



Spike solitary. PediceUate spikelets lanceolate, flattened, with 2 male 

 flowers. — 4. I. laxxim. 



1. /. arundinaceum, F. v. M. — Roper River, F. v. Mueller ; Port Darwin, 

 Sohultz (Nos. 30, 182, 815). 



2. /. australe, B.Br. — ^N. AustraHa, near Sea Range, F. v. Mueller. 

 Var. villosum, Benth. — ^Near 5-Mile Bar, MacArthur River, G. F. HUl 



(No. 740), 6/2/1912. 



Recorded. North Coast, R. Brown. 



3. /. decumbens, Benth. — Port Darwin, Schultz, (No. 126). 



4. I. laxum, B. Brown. — ^Newcastle Waters, G. F. Hill (No. 494), 

 7/7/1911 ; MacArthur River, G. F. HiU (No. 743), 7/2/1912. 



Recorded. Islands of the Gulf of Carpentaria, R. Brown ; mainland of the 

 Gulf, Landsborough ; Victoria River, F. v. MueUer ; Port Darwin, Schultz 

 (No. 10) ; Arnhem's Land, M'Kinlay. 



5. /. truncatiglumis, F. v. M. — Arnhem's Land, F. v. MueUer. 



/. pectinatum, Trin, recorded in National Herbarium Census from North 

 Austraha. 



9. ANDROPOGON, Linn. 1735. 



(Agenium, Nees, 1836. Alloianthena, Steud., 1855. AUoiatheros, Rafln, 

 1830. Anadelphia, Hack, 1885. Anatherum, Beauv., 1912. Anthrostachys. 

 Desv., 1831. Cymbachne, Retz., 1791. Cymbogon, Spreng, 1815. Dichan- 

 thium, Willem, 1796. Drectonis, H. B. and K., 1815. Dischanthium, Kunth, 

 1833. Eriopodium, Hochst, 1846. Exotheca, Anderss., 1856. Graya, Arn., 

 1840. Gymnandropogon, Duthie, 1878. Depeocercis, Trin., 1820. Oropogon, 

 Neck., 1790. Pithecurus, Willd., 1833. Schizachyrium, Nees, 3829. Schizo- 

 pogon, Reichb., 1828. Vetiveria, Thou., 1827.) 



Spikelets in pairs along one side of a simple spike or of the spikehke 

 branches of a simple panicle. 



Spike single. Spikelets unisexual, the awned females turned to one side, 

 the awnless males imbricate behind them. (Heteropogon). 



Spikes about 2 in. long ; male spikelets 3 to 4 hnes. — 6. A. contortus. 

 Spikes 3 to 6 in. long ; male spikelets \ in. — 18. A. triticeus. 



Spikes sohtary, digitate, or several nearly sessile on a simple rachis. 

 Sessile spikelet 1- flowered and fertile pedicellate one male or neuter. (Andro- 

 pogon.) 



- Spikes 2, 3 or more, clustered at the end of a peduncle without sheathing 

 bracts, very rarely reduced to a single spike. 



Spikelets concealed or nearly so under copious long silky hairs. 



Long silky hairs on the back of the outer glumes as well as on the rachis 

 and pedicels. — 17. A. sericeus. 



Long silky hairs only or chiefly on the rachis and pedicels. — 2. A. affinis. 



Spike silky hairy, but the hairs not covering the spikelets. 



Spikes 3 or 4 in a close cluster. Outer glumes obtuse or toothed. — 

 3. A. annulatus. 



Spilies numerous, the common axis elongated. — 11. A. intermedins. 



Spikes 2 together on each peduncle within or above a sheathing bract. 



