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Lactuca Linn.

莴苣属

Description from Flora of China

Agathyrsus D. Don; Lactucopsis Schultz Bipontinus ex Visiani; Lagedium Soják; Mulgedium Cassini; Phaenixopus Cassini; Pterocypsela C. Shih; Scariola F. W. Schmidt; Steptorhamphus Bunge.

Herbs, perennial or annual, more rarely subshrubs (only Lactuca orientalis in China). Stems usually leafy. Leaves pinnate or undivided. Capitula with 4-30 or more florets. Involucre narrowly cylindric. Phyllaries glabrous or hairy; outer phyllaries gradually longer centripetally, ± imbricate, often ca. 1/2 as long as inner phyllaries or even ± approaching them in length; inner phyllaries usually 3, 5, or 8, ± linear-lanceolate to linear, often of unequal length in fruit. Receptacle naked. Florets some shade of yellow or blue. Achene narrowly or broadly ellipsoid, body subcompressed to compressed, between 2 thicker or wider lateral ribs with 1 to several slender ribs on either side; beak usually present, stout, slender, or filiform. Pappus white or sometimes with a faint yellow tinge, single, of slender scabrid bristles [or double with an additional outer row of minute hairs].

The circumscription of the genus is not yet settled, and species numbers given in the literature therefore vary greatly. The concept of the genus applied here on the basis of molecular and morphological studies by N. Kilian et al. (in prep.) is wider than the one adopted in FRPS (80(1): 233-239. 1997) and includes, as far as China is concerned, the former segregates Mulgedium, Pterocypsela, and Scariola.

Probably ca. 50-70 species: mostly in C and SW Asia, Europe, North America; 12 species (one endemic, one introduced) in China.

(Authors: Shi Zhu (石铸 Shih Chu); Norbert Kilian)

Lower Taxa


 

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