290 Class XIX. Order I. 



spines. Peduncles axillary and terminal, covered with a white, 

 line, deciduous down. Calyx smooth, swelling out at base. Co- 

 rolla yellow. Flowers about half the size of the dandelion. 

 Down fine and smooth. September. Annual. 



* SONCHUS SPINULOSUS. Prickly Sea Sonchus. 



S. foliis amplexicaulibus, oblongis, undulatis spinu- 

 losis ; floribus subumbellatis. 



Leaves clasping, oblong, waved, prickly ; flowers 

 somewhat umbelled. 



Stem smooth, few angled, two feet high. Leaves smooth, ob- 

 long, heart shaped at base, the lobes curling backward and clasp- 

 ing the stem, the edges waved, acutely toothed, the teeth end- 

 ing in short spines. Flower somewhat umbelled, small, yellow. 

 Peduncles smooth, sometimes furnished with very few glandular 

 hairs. Calyx swelling at base, smooth, its scales acuminate and 

 nppressed. -Salt marshes. August. Annual. 



SONCHUS ACUMINATUS. Willd. Blue Sonchus. 



Peduncles somewhat scaly ; flowers panicled ; low- 

 er leaves runcinate, upper ones ovate, acuminate, pe- 

 tioled, toothed in the middle. 



This plant differs from the species before described, in having 

 blue flowers. These are rather small and numerous. Low 

 grounds, rare. August. Biennial. 



307. ARCTIUM. 



ARCTIUM LAPPA. L. Burdock. 



Leaves heart shaped, unarmed, petioled. L. 



No plant is better known than this. Its very large, heart- 

 shaped, wavy leaves cover the ground for some extent around it. 

 The stem, which rises three or four feet, is branching, rounc 1 , 

 furrowed, and rough. Flowers numerous, terminal, purple. 

 This plant intrudes itself on every one's acquaintance by the 

 sharp, firm hooks at the end of the calyx scales, which attach 

 themselves to the clothes, and serve as a remarkable mechanism 

 for dispersing the seeds. Common in waste and cultivated 

 ground. July, August. Perennial. 



