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FOC | Family List | FOC Vol. 20-21 | Asteraceae | Taraxacum

2. Taraxacum sect. Leucantha Soest, Wentia. 10: 6. 1963.

白花蒲公英组 bai hua pu gong ying zu

Leaves and scapes sparsely arachnoid to subglabrous. Capitulum erect after anthesis. Outer phyllaries (9 or)10-16(-19), greenish to dark green, imbricate or sometimes not so, ovate to lanceolate, usually tightly appressed, border paler or reddish and usually broad or less often narrow or absent, usually not corniculate near apex. Florets white, whitish yellow, pale yellowish (more deeply yellow in center of capitulum), or yellow. Achene pale grayish or brownish straw-colored, subdensely coarsely spinulose with subacute stout spinules often slightly curved upward, apically subgradually to subabruptly narrowing into a usually subcylindric 0.7-1 × 0.4-0.5 mm cone; beak 5-7 mm, sometimes thick but usually thin. Pappus white or brownish discolored, 5-7 mm.

About 23 species: Afghanistan, China, India, Mongolia, Kazakhstan, Kyrgyzstan, Pakistan, Russia, Tajikistan; 13 species (four endemic) in China.

Part of the sectional diversity center is in SW China.

In Hebei, Nei Mongol, Shaanxi, and Shanxi sexual representatives of Taraxacum sect. Leucantha were detected. They are very variable in leaf shape and by their outer phyllary characters belong to the group of T. sinicum and T. dealbatum. Further research is needed.

Taraxacum leucanthum (Ledebour) Ledebour (Fl. Ross. 2: 815. 1846) has been reported as a member of the Chinese flora (FRPS 80(2): 14. 1999; Higher Pl. China 11: 769. 2005). The name usually covers most of the diversity of the whole section in the literature. We failed to find any specimen belonging to this species in the material studied. However, T. leucanthum might be found in NW Xinjiang. High mountain plants from Gansu, Qinghai, and Xizang reported in the literature under this name belong to other taxa (in part, probably to T. candidatum), but a revision is inevitable.


1 Pollen absent   (2)
+ Pollen present   (4)
       
2 (1) Outer phyllaries evenly black to blackish green, border not developed.   2 T. albiflos
+ Outer phyllaries green to dark green in middle, paler borders developed   (3)
       
3 (2) Scapes glabrous; achene cone 1-1.1 mm, beak 5-6 mm.   4 T. niveum
+ Scapes arachnoid; achene cone 0.7-1 mm, beak 4-5 mm.   6 T. candidatum
       
4 (4) Pollen grains regular in size (plants sexual).   (see comment above)
+ Pollen grains irregular in size   (5)
       
5 (4) Stigmas yellow or ± yellow   (6)
+ Stigmas discolored (grayish, greenish, dark, yellowish green)   (8)
       
6 (5) Achene beak 2-3 mm, thick.   8 T. armeriifolium
+ Achene beak 4-5 mm, thin   (7)
       
7 (6) Achene 3.5-3.9 mm; pappus 4-5 mm.   11 T. pseudoleucanthum
+ Achene 5.2-5.7 mm; pappus ca. 7 mm.   12 T. iliense
       
8 (5) Inner florets involute to subtubular, cream to pale yellowish white.   14 T. cereum
+ Inner florets canaliculate, all yellow or at least only outer ones white   (9)
       
9 (8) All florets yellow   (10)
+ At least outer florets ± white inside   (12)
       
10 (9) Involucre base rounded, 7-10 mm wide; outer phyllaries ovate to broadly ovate.   9 T. ikonnikovii
+ Involucre base ± subobconic, 6-8 mm wide; outer phyllaries ovate-lanceolate to lanceolate   (11)
       
11 (10) Leaf lateral lobes linear to linear-triangular, not lingulate; achene 3.5-4.4 mm, cone 0.7-1 mm.   7 T. sinicum
+ Leaf lateral lobes lingulate; achene 4.5-4.8 mm, cone 1.2-1.5 mm.   13 T. patiens
       
12 (9) Outer phyllaries with dark blackish green middle part, border white and 0.9-1.3 mm wide.   3 T. album
+ Outer phyllaries with green to dark green middle part, border whitish and 0.5-1 mm wide   (13)
       
13 (12) Pappus ± yellowish white.   5 T. dealbatum
+ Pappus conspicuously brownish pinkish white.   10 T. luridum

  • List of lower taxa


     

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