Ambrosia.] LXV. COMPOSITE. 867 



1- A. maritima (a seaooast plant), Linn, in Fl. Trop. Afr. iii. 870. A 

 coarse annual, woody below, 1 to 3ft. high (in Queensland 6 to 8ft.), whole plant 

 usually very hairy and hoary, much-branched. Leaves ovate, bipinnatipartite, 1 

 to Sin. long ; segments obtuse, sometimes toothed. Flower-heads subsessile, ^ to Jin. 

 diameter, 15 to 20-flowered, in dense spikes or racemes, male at the top and often 

 female below, arranged in a pyramidal or corymbose terminal panicle, leafy at 

 least below. Male involucres crenate, shortly hemispherical, hispid with upcurved 

 scattered hairs ; fruiting involucres somewhat turbinate and angular, with 4 or 5 

 horns at the top. — Oliver, I.e. 



Hab.: This tropical African plant, which is widely spread throughout the Mediterranean region, 

 and most warm countries, has of late years been introduced in fodder seeds, and, unfortunately, 

 has taken but too kindly to our soil, and doubtless, after years, may become as widespread as its 

 allies, the Bathurst and Noogoora Burrs. 



52. -XANTHIUM, Linn. 



(From xanthos, a yellow dye having been obtained from the plants.) 



Flower-heads monoecious ; males globular. Involucral bracts small, in a 

 single row. Receptacle cylindrical, with chaffy scales between the florets. 

 Florets numerous, tubular, 5-toothed, without styles. Female-heads ovoid. 

 Involucral bracts in 2 or 3 rows, the outer small, the 2 innermost large, con- 

 solidated into a hard ovoid 2-celled mass, very prickly outside, and terminating 

 in 2 tubercles or cones. Florets 2 without corollas. Ovaries each immersed in 

 one of the cells of the involucral mass, the styles protruding with filiform 

 branches. Achenes obovoid, enclosed in the burr-like involucre. Pappus none. 

 — Coarse annuals. Leaves alternate. Flower-heads in axillary or terminal 

 clusters or short racemes. 



A genus of 2 or 3 species, natives of the Mediterranean regions and the Levant, or one perhaps 

 of Chilian origin, all now spread as weeds over many parts of the world. — Benth. 



Plants spiny. Leaves lanceolate, trifid 1. X. spinosum. 



Plants without spines. Leaves deltoid, 3 to 5-lobed 2. A', strumarium. 



1. X. spinosum (plant spiny), Liiw. DC.' Prod. v. 495 ; Benth. Fl. Aiistr. 

 iii. 535. Bathurst Burr. A rigid much-branched annual of 1 to 2ft., studded 

 with numerous strong trifid spines usually opposite in pairs or rarely solitary, 

 divaricate, placed at the base of the leaves but rather within the petiole. Leaves 

 lanceolate, trifid, with the central lobe much longer than the lateral ones, slightly 

 scabrous above, white-tomentose underneath. Flower-heads in axillary clusters 

 or almost solitary, the upper ones male, the lower female ; these are sessile, 

 forming when in fruit oblong burrs about |in. long, covered with hodked prickles, 

 the terminal conical beaks exceedingly short, often both reduced to mere tubercles 

 or one only slightly elongated. 



Hab.: Supposed to be of Chilian origin. Abundant in many southern parts. 



2. X. Strumarium (from struma, a swelling), Li)m. Noogoora Burr. A 

 tall wide-spreading annual often attaining a height and breadtli of 8ft, Leaves 

 scabrous, deltoid, 3 to 5-lobed, often unequally, coarsely toothed, 3 to 6in. wide, 

 3-nerved at the base, cordate, sinus wide, cuneate into the petiole of 1 to 5in. 

 Heads nearly sessile, clustered. Fruits (burrs), Jin. or more long, terminating. 

 in erect or somewhat curved beaks. 



Hab.: A widespread weed of warm countries. Very abundant in southern parts. 



