Lactuca COMPOSITAE Ixeris 



bb. Beak of the pale brown or mottled frs. filiform, 

 exceeding the body: plants cultivated for the lvs. 



and fleshy stems 3. L. sativa 



aa. Involucres 5-fld. ; their bracts consisting of a single inner 

 series, surrounded by a number of minute, deltoid outer 

 ones: fls. purple : frs. slightly flattened 4 . L. diversifolia 



1. Lactuca raddeana Maxim. (L. elata Hemsl.) \1\^% (Shan K'u TVai) (St. P. B. 19:526). 

 Erect herb, to 1.3m.; fls. pale yellow, VIII-IX. Eastern Asia; locally in An., 

 Che., Hup., Ki. Woodland and clearings. 



Comparison of authentic material of L. elata with specimens of L. raddeana from both 

 Siberia and Japan reveals no significant difference between them. 



2. Lactuca indica Linn. (L. furmosana Hemsl., non Maxim.) (H.F.3:405). Erect 

 herb, to 2 m.; fls. pale yellow or white, IX-X. Eastern Asia; locally in Hup., 

 Ki., Ku. Fields, roadsides, clearings. 



2a. Lactuca indica Linn. ssp. laciniata (Houtt.) Stebbins (L. laciniata (Houtt.)Mak.) 

 (Mak.F.6). Erect herb, to 2 m.; fls. pale yellow or white, VII-X. Eastern Asia; 

 locally in Ku. Fields and open places. 



The laciniate-leaved form of L. indica is the only one commonly found in the northern 

 part of its range, while southward only the entire-leaved form occurs. In central and eastern 

 China the two overlap, and every intergradation between them is found. 



3. Lactuca sativa Linn. Lettuce ^H; (Wo Chii) (B.M.984). Erect herb, to lm.; 

 fls. yellow. Cultigen; locally in An., Che., Ki., Ku. Cultivated, leaf-vegetable. 



3a. Lactuca sativa Linn. var. asparagina Bailey Asparagus Lettuce (B.M.984). Erect 

 stem fleshy and edible. Locally in An., Ku. 



4. Lactuca diversifolia Vaniot (Bu.G.B. 12:245). Erect herb, to lm.; fls. purple, 

 VII-VIII. China; locally in An., Che., Hup. Woodland, thickets. 



This species is nearest to L. sororia Miq. of Japan and southern China, from which it is 

 distinguished by its glabrous pedicels (glandular in L. sororia), 5-flowered involucres (8-12- 

 flowered in L. sororia) and slightly smaller achenes. 



56. Ixeris Cass. 3%-f!$.M (Chien Tsu Ku Shu) 



Glabrous (rarely pubescent) mostly low herbs: lvs. entire or pinnatifid: infl. 

 cymose: involucre of a single series of inner bracts and a few small outer ones: fls. 

 yellow, white or purplish; corolla tube short, less than 1/2 as long as the ligule, 

 glabrous or scabrous: frs. small or large, beaked (except in /. laneeolatd) slightly 

 obcompressed, 10 (in forms of /. denticulata 12-15) -ribbed: the ribs equal, prominent, 

 sometimes alate; pappus setae white or yellow; all of them more than 4-celled in 

 cross section at the base; ovary with 5 vascular bundles. 25-30 species, in Asia; 

 10-12 from China. 



Species relationships within this genus (except for /. denticulata) are made very com- 

 plex by the presence of polyploidy and parthenogenesis. Many of the forms are polyploid, 

 sexual or parthenogenetic forms of hybrid origin. A true understanding of this genus will be 

 attained only after careful herbarium and field studies by a specialist. The key presented is, 

 therefore, frankly tentative. 



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