456 



THE COMPOSITE FAMILY. 



cut into 3 or 5 lanceolate segments, and 

 in the flower-heads rather less droop- 

 ing. 



Its geographical range and stations 

 are the same as those of the drooping 

 2?., but it appears to be rather less 

 common in Britain. Fl. summer and 

 autumn. 



Fig. 545. 



XX. BURWEED. XANTHIUM, 



Coarse annuals, with alternate leaves, and unisexual, axillary or ter- 

 minal heads of green flowers. Involucre of the males of several bracts 

 in a single row, enclosing many tubular florets, separated by the scales 

 of the receptacle. Anthers free. Female florets 2 together, combined 

 with the involucre into an ovoid or oblong, prickly burr, terminating 

 in 2 beaks, from which the stigmas shortly protrude. 



A genus of two or perhaps three species, from the Mediterranean 

 region to the Levant, but spread as weeds of cultivation over a great 

 part of the globe. Its immediate connection with the remainder of 

 Composites can only be traced through several exotic genera forming 

 the small tribe of Ambrosiece, the general habit and unisexual flowers 

 showing at first sight some analogy to the Nettle family, and some 

 other Monochlamyds. 



1. Broad Burweed. 



Xanthium Strumarium, Linn. 

 (Fig. 546.) 



(Eng. Bot. t. 2544.) 



A coarse, erect annual, 1 to 2 feet high. Leaves on long stalks, 

 rather large, broadly heart-shaped, coarsely toothed or angular, rough 



