Silphium Silybum . 189 



heads of light yellow flowers. The leaves are ovate- 

 oblong, thick and rough, especially beneath, and from 

 i ft. to 2 ft. long, on slender stalks. A variety (pinna- 

 tifidum) has the leaves deeply cut or pinnatifid. This 

 species is remarkable for its strong turpentine odour. 

 Division. N. America. 



* Silphium trifoliatum. This species has a smooth, 

 often glaucous, rather slender stem, from 4 ft. to 6 ft. 

 high, branching above. Leaves lance-shaped, pointed, 

 entire or scarcely serrate, short-stalked, in whorls of three 

 or four, the uppermost ones opposite. Flower-heads 

 yellow, more than 2 ins. across, on long stalks, and form- 

 ing loose panicles. Division. N. America. 



* Silybum marianum (Milk-thistle). A very ro- 

 bust and vigorous-growing native biennial, 5 ft. or more 

 in height, of strikingly handsome appearance, and well 

 deserving to be associated with other large fme-foliaged 

 plants. Its leaves are of very great size, variously cut 

 and undulated, tipped and margined with scattered spines, 

 and of a bright glistening green colour marbled and 

 variegated with broad white veins. Easily raised from 

 seed, and thrives in almost any kind of well-drained soil. 

 Additional vigour and development may be thrown into 

 the foliage by pinching off the flower-stems on their first 

 appearance. If a few plants are raised in the garden 

 and planted out in rough and somewhat bare places or 

 banks, etc., this will soon establish itself permanently. 



Silybum eburneum is a more tender species, very 

 closely resembling the above, but with spines which 

 appear as if made of ivory. It is also more constantly 

 biennial, and in consequence its leaves are almost always 



