COMPOUND FLOWERS 



157 



3. L. saligna (Willow Lettuce). More slender than the last, 

 leaves narrower, and perpendicular against the stem ; variable and 

 likely to be confounded with L. scoriola. Rare ; confined in 

 Britain to chalky situations, in the south-east, near the coast. Fl. 

 July, August. Biennial. 



4. L. Alpina (Alpine Lettuce, or Blue Sow-thistle). A handsome 

 erect, unbranched plant 2-3 feet high, with a panicle of large blue 

 flower -heads. It grows on the Clova Mountains, but is rare. Per- 

 ennial. Known also as Sonchus Alpinus. The Garden Lettuce 

 (L. sativa) belongs to this genus, but is not a native plant. 



8. Sonchus (Sow-thistle) 



1. S. oleraceus (Common Sow-thistle, 

 Milk-thistle). Erect, branched, 1-4 

 feet high ; stems hollow ; leaves oblong, 

 more or less pinnatifid or entire, 

 toothed, often prickly, the upper ones 

 often clasping the stem with spreading, 

 arrow-shaped auricles ; heads some- 

 what umbellate ; involucres smooth. 

 Waste places, and as a garden weed ; 

 common. This plant makes light and 

 salutary meals for rabbits. Fl. June to 

 September. Annual. 



2. 5. arvensis (Corn Sow-thistle). 

 Stem simple, 2-4 feet high, tubular, 

 angular ; leaves oblong, pinnatifid or 

 wavy, toothed and spinous. The lower 



ones stalked and heart-shaped at the Sonchus Oleraceus 



base ; upper clasping the stem with (Common Sow-thistle, Milk-thistle) 

 auricles ; loose corymbs of large yellow 



flower-heads ; involucre and flower-stalks with dark glandular 

 hairs. In similar situations with the last, from which it may be 

 readily distinguished by its simple stem and much larger flowers. 

 Fl. August, September. Perennial. 



3. S. palustris (Marsh Sow-thistle). Much resembling the last, 

 but taller ; stem 6-8 feet high, unbranched ; leaves long, narrow, 

 clasping the stem with pointed auricles ; flower-heads large, pale 

 yellow ; involucres with glandular hairs. Marshes in the south- 

 east of England ; very rare. 



A variety of S. oleraceus, frequently found growing with it, is 

 S. .asper (Rough Sow- thistle). The leaves are more spinously toothed, 

 with rounded auricles, and darker in colour, whilst the longi- 

 tudinal ribs of the achenes are not transversely wrinkled. 



