1272 
MESSES. J. B. LAWES, J. H. GILBEET, AND M. T. MASTEES, 
Composite. 
This, the largest group of flowering plants known, comprises a vast assemblage of 
species greatly alike as to their floral characters, but differing much in the appearance 
of their stem, leaves, &c. The chemical products also vary greatly. The species 
represented on the plots are : Centaurea nigra, found on a majority of the plots, 
Carduus cirvensis on very few, Beilis perennis on more, but still only on a few, 
Achillea Millefolium on almost all, Chrysanthemum Leucanthemum on very few, 
Senecio erucifolius only once, Hypochceris radicata occasionally, Tragopogon pra,- 
tensis on several, Leontodon hispidus also on several, L. autumnalis less frequently, 
Taraxacum officinale on a considerable number, Sonchus oleraceus only once, and 
Hieracium Pilosella in a few instances. 
Centaur ea nigra. 
This common weed of pasture land forms a densely-tufted, much-branched, 
perennial, with a tough, woody stock, from which descend long, stout, deeply- 
penetrating roots. The stems are erect, rigid, 1 to 2 feet high, and branched, the 
branches ending in hard globose flower-heads. It flowers too late to produce seed 
in the first crop. 
The qualities favourable to its persistence or spread are its hardiness and power of 
withstanding drought, and, where permitted to ripen, its free-seeding. 
The following table shows the relative degree of prominence of this plant. 
