60 COMPOSITE. TRIBE III. 



5. C. acaulis. Willd. (Stemless Dwarf Plume Thistle.) 

 Dry gravelly pastures. 7-9. 

 Not unfrequent on Ruislip Common. 



CENTAUREA. (Knapweed.} 



1. C. nigra. L. (Common Black Discoid Knapweed.) 

 Meadows and pastures. 6-10. 



Abundant everywhere. In the field behind the Grove, 

 Harrow, I once found a rayed variety, which perhaps is 

 C. nigrescens, Godr. (Black-rayed Knap weed.) (Edition i.) 



2. C. Cyanus. L. (Corn Blue Bottle.) 

 Corn-fields and waste ground. 6-8. 

 Near the Chalk Pits, Pinner. 



TKIBE III. C OR Y MBIFE R.E . 



BIDENS. (Bur Marigold. 



1. B. cernua. L. (Nodding Bur Marigold.) 

 Sides of rivulets, ditches, etc. 7-10. 



Pools at Harrow. Weald Stone. Stanmore Heath. 

 (Flor. Midd.) Larger than the next in all its parts. 



2. B. tripartita. L. (Trifid Bur Marigold.) 

 Marshy places, sides of ponds. 7-9. 



Pond in a field near the junction of the Perivale and 

 Greenford Roads, Grove Pond, and by a pool at Greenhill. 

 Kingsbury . (Farrar. ) 



EUPATORIUM. (Hemp Agrimony.) 



I. E. cannabinum.* (Common Hemp Agrimony.) 



Banks of streams and ditches. 8, 9. 



A single chance plant at Pinner. (Bank of the Colne 

 near Hamper Mill, beyond the limits of the Harrow district.) 



