T. W. KiKK. — On Xanthium strumarium in N.Z. 311 



Some time ago the " Silverstream," from Buenos Ayres, 

 discharged a quantity of earth-ballast, which was placed inside 

 the railway-fence on the Bunny Street frontage. A few months 

 later this heap w^as observed to be covered with a luxuriant 

 growth of weeds, and from it I collected no less than seventeen 

 species — many of them, unfortunately, already too well known 

 in the colony ; but two or three have, apparently, not been 

 previously recorded here. Amongst these last was the subject 

 of the present note — viz., Xanthmm strumarium, known in 

 England as the small burdock, or burr-weed ; in America as 

 the clot, or cockle burr ; and in Australia as the Noogoora burr, 

 from the locality where it was first observed to be injurious. 



The plant belongs to the order CompositcB, but the young 

 botanical student would probably at first, on account of the 

 separation of the male and female flowers, have some difficulty 

 in understanding why it should be so classed ; a further and 

 careful examination will, however, convince him of its true 

 relationship. 



Xanthium, Linn. (From ^av^os, yellow; the plants being 

 formerly used by the Greeks to dye their hair.) 

 Capitula unisexual, monoecious ; staminate globose, in ter- 

 minal clusters ; pistillate 2-flowered, chiefly axillary. Male 

 capitula with few narrow involucral bracts ; florets numerous, 

 sheathed by folded hyaline palese ; corolla 5-toothed ; anthers 

 free or nearly so, base obtuse. Female capitula with an ellip- 

 soidal or ovoid closed gamophyllous aculeate involucre, 2-lobel- 

 late and 2-rostrate ; corolla none ; achenes solitary in each cell 

 of the indurated prickly enclosing involucre. Coarse, scabrid, 

 hoary, or glabrate annuals, with alternate petiolate palmately- 

 lobed leaves. 



X. strumarium, Linn. — Stem, branches, and leaves puberu- 

 lous without spines, mottled, spreading, attaining a height of 

 6ft. or 8ft. Leaves deltoid, 3- to 5-lobed, unequally, often 

 coarsely dentate, often over Gin. broad ; base 3-nerved, cordate, 

 sinus wide, cuneate into the petiole of lin. to Gin. Capitula 

 nearly sessile, clustered ; fruit ellipsoidal, about fin. long, 

 terminating in an erect or somewhat curved beak. (Bailey.) 



The female flower-heads are in small axillary clusters of 

 two or three, the male flower-heads being placed above them, 

 at the top of the branchlets. After the pollen has been dis- 

 persed, the male flowers soon drop off, and the female flower- 

 heads rapidly develope into oblong burrs, very hard, and 

 thickly studded with hooked spines. On the top of the burr 

 are to be seen two very stout beaks, and within will be found 

 two cells, each with a single seed. 



This plant is a rank annual weed, and in Australia grows 

 to' a height of Gft., 8ft., or in some cases 10ft., with wide- 



