65 



Habitat and range. — The original home of this grass is given in the 

 Index Keivensis as the Mediterranean region and Afghanistan. It is 

 common in the sandy soils of the plains of Northern India, and is 

 described by Bentham as a common weed in most tropical and tem- 

 perate regions in the new and old world. There is no doubt, however, 

 that it is an indigenous Australian plant. The Baron informs us that 

 up to the present it has been found in all the colonies, save only Tas- 

 mania and Western Australia. 



This is one of those grasses which have been more widely diffused, 

 though accidentally, by the agency of man. On the advent of the 

 white man to this Colony it was found in the arid interior portions of 

 it, but gradually it has worked its way coastwise, mainly, and perhaps 

 entirely, through the burrs becoming entangled in the wool of sheep, 

 or through the sweepings of the sheep-trucks containing seed-laden 

 manure. So rapidly do sheep-trucks now come from such places as 

 Hay, Narrandera, Gunnedah, &c, that the transmission of interior 

 plants to the coast is proceeding at a rapid rate. To give but one 

 instance ; fettlers on the Southern line will inform you that the small 

 introduced musk-melon fCucumis myriocarpus, Naud.) constantly ger- 

 minates on the permanent -way, distributed through the droppings 

 from the sheep-trucks. 



Our grass under notice I have traced on the railway line at different 

 places, and finally near the Homebush sheep sale-yards near Sydney. 



Reference to plate. — A, spikelike panicle ; b, part of the panicle enlarged ; c, a " burr,' 

 consisting of a pair of narrow spikelets opened out. 



16. NEURACHNE. 



Spikelets with one terminal hermaphrodite flower, and very rarely a 

 second male one below it, sessile along the continuous rhachis of a 

 simple ovoid or cylindrical spike. 



Glumes four, the second the largest, fringed on each side, at least 

 in the lower half, with long spreading cilia on the intramarginal 

 nerve. 



Third glume smaller and thinner, usually with a small palea in its 

 axil. 



Fruiting glume smaller, thin, and often hyaline. 



The palea also very thin, as long as or longer than the glume. 



Styles distinct. 



Grain enclosed in the thin palea and glume, free from them. 



Spike ovoid or oblong, f to 1 inch long ; outer glume five- or seven- 

 nerved, with long spreading hairs on the back ... .. 1. N. alopecuroidea. 



Spike narrow, 1 to 2 inches long. Outer glume with a transverse 

 callosity on the back bearing long cilia, and below it an ovate 

 very thin space, bordered by a thickened margin ... 2. N. Mitchelliana. 



Spike narrow, 1 to 2 inches long. Outer glume thin, glabrous, or 



bordered by very few cilia 3. N. Munroi. 



E 



