<^- 



HORN EXPEDITION — BOTANY. 191 



XANTIIOrvRHCEA TlIORXTOM, Tate. 



Caudex attaining to a lioight of six feet and a circumference of three. 

 Leaves slender but rigid, four feet long, strictly quadrangular, about two milli- 

 metres in diameter, interstriated (about nine stri:e on eacli face); margins acute, 

 minute crenate-serrate. 8cape seven feet long, inclusive of tlie spike wliich is five 

 and a half feet. Inner bracts crustaceous, ol)long, obtuse, undulate on tlie margins, 

 smooth and sinning, witliout veins, about half tlie lengtli of the capsule. Outer 

 bracts linear with spathulate tips, without veins ; the outermost ones with Ijro.idly 

 decurrent bases. Flowers not seen. Capsule one incii or more in length ; the 

 valves broadly lanceolate, abruptly narrowed into a long somewhat pungent-pointed 

 tip ; the upper-half of the outer face finely longitudinally furrowed. Seeds oblong- 

 elliptic in longitudinal outline, acutely triangular in transverse section, black, 

 minutely granulated ; outer face convex, longitudinally ridged ; the inner narrow 

 faces separated by an acute medial ridge. 



The species name is in compliment to Mr. Thornton, late of Tempe Downs, 

 wlio at considerable trouble was the first to bring this grass-tree to my notice, and 

 in other directions greatly forwarded the ol)jects of the Expedition. 



This species by its foliage resembles the southern A', qiiadrang^ulata, fr-om 

 wliich it conspicuously differs by its scape, very mucli shorter than the spike ; also 

 Ijy its longer and narrower capsule, and relatively shorter subtending liracts. 

 X. Preissii, to wliich it is g(>ographically nearest, is somewhat intermediate 

 between X. Tliorntoiii and X. iji/adraugiilafa as regards the proportionate length 

 of the flower-bearing portion of the scape ; but the foliage among other characters 

 is diflerent. 



Chapter II. — The Central Eremian Flora. 

 1. Physiographic and Botanic Characteristics of the Region. 



That portion of the central Eremian region travelled over by the Expedition 

 from Oodnadatta to Engoordina, by way of Dalhousie Springs on the out-journey, 

 and back by way of the River Stevenson, has been fully wi-ll ex[)lored for its 

 botany. And though every opportunity wa.s availed of, yet only a very limited 

 number of species is worthy of note, some because new to the region (including 

 one, Threlkeldia proceriflora, previously unknown in South Australia), others 

 because reaching their most northern or southern limits in the meridional ilirection, 



