Sonchus 



COMPOSITAE 



Lactuca 



coarse, others copious, very slender and flexuous, mostly 2-celled in cross section, 

 adhering to clothing, etc. 40-45 species, in the eastern hemisphere; 3 introduced in 

 and perhaps 1 or 2 native to China. Ours all cosmopolitan weeds. (The ancient 

 Greek name.) 



Key to the Species 



Perennials with creeping rhizomes: heads 4-5 cm. wide 1. S. arvensis 



Annuals or biennials: heads smaller. 

 Lvs. not strongly spiny: frs. about lmm. broad, broadest above the 



middle, rugose 2 . S. oleraceus 



Lvs. strongly spiny: frs. about 1.5mm. broad, elliptic, broadest at the 



middle, not rugose 3. S. nsper 



1. Sonchus arvensis Linn. Field Sow-Thistle ^ffl^ (K'u Mai Ts'ai) (G.M.1553). 

 Erect perennial, to lm. ; fls. yellow, VIII-X. Temperate and subtropical regions; 

 locally in Hun., Ku. Fields and waste places. 



2. Sonchus oleraceus Linn. Common Sow-Thistle t^j^ (K'u Ts'ai; Bitter Vegetable) 

 (G.M.1554). Weedy herb; fls. yellow, IV-VIII. Temperate and subtropical regions; 

 locally in Hun., Ku. Waste places. 



3. Sonchus asper (L.) Hill Spiny-leaved Sow-Thistle }£ji , ) 'r (Nan Ts'ao) (G.M.1554). 

 Weedy herb; fls. yellow, IV-VIII. Temperate and subtropical regions; locally in 

 Ku. Waste places. 



55. Lactuca Linn. Lettuce ^"^M (Wo Chii Shu) 

 Ours tall or medium sized lfy. -stemmed herbs with racemose -paniculate infl'-s' 

 involucres narrow, 5-30-fld.; their bracts various: fls. yellow, white, lavender or 

 purplish; corolla tube elongate, 1/2 as long as to equalling the ligule, glabrous below, 

 but with a ring of soft hairs about the apex: frs. definitely flattened, beaked, or at 

 least strongly contracted at the apex, variously ribbed, but with the two lateral ribs 

 always stronger than the others; pappus setae delicate and fragile, at least some of 

 them only 2-4-celled in cross section at the base. 90-100 species, in the Old World, 

 North America and the West Indies; 28 in China. (Latin: lac, milk; referring to the 

 milky juice.) 



Key to the Species 



a. Involucres 12-30-fld.; their bracts evenly imbricated in 



several series: fls. yellow or white: frs. strongly 



flattened. 



b. Beak of the dark brown or black frs. shorter than 



the body: native plants. 



Beak of the frs. very short and thick, or none; frs. 



with 3-5 ribs on each face 1 . L. raddeana 



Beak of the frs. slender, 0.7-1.3 mm. long; frs. 

 with a single rib on each face. 

 Lvs. entire or remotely few-lobed: aggregate infl. 

 broadly cylindric or pyramidal, its lower brs. 



elongate 2. L. indica 



Lvs. lanciniate-pinnatifid: aggregate infl. mostly 

 cylindric or ovoid; its lower brs. not at all or 

 only slightly longer than the middle ones 2a. L. indica ssp. laciniata 



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