All Floras      Search Specimen
Login | eFloras Home | Help
IBSC | Family List | Compositae

Youngia Cass.

黄鹌菜属

Description from Flora of China

Pseudoyoungia D. Maity & Maiti.

Herbs, perennial or annual, acaulescent or caulescent, often ± rosulate, glabrous or somewhat to sparsely arachnoid hairy or pubescent. Synflorescence corymbiform or paniculiform-corymbiform, exceptionally secundly racemiform. Capitula with 5-25 florets. Involucre cylindric, cylindric-campanulate, campanulate, or broadly cylindric. Phyllaries abaxially glabrous or more rarely somewhat arachnoid hairy, very rarely glandular; outer phyllaries few to several, centripetally longer, at most 1/4(-1/2) as long as inner ones; inner phyllaries usually linear-lanceolate, equal in length, midvein subapically crested and corniculate or flat. Receptacle naked. Florets yellow. Achene ± fusiform, columnar, or ± cylindric, inconspicuously compressed or subcompressed, with 4 or 5 main ribs each accompanied by (1 or)2 or more slender secondary ribs, ribs usually finely spiculate especially apically, apex attenuate or rarely with a stout short beak. Pappus white, rarely gray or pale brownish, scabrid.

The circumscription of Youngia has recently been changed by Sennikov and I. D. Illarionova (Komarovia 5: 96. 2008) based, in particular, on carpological analyses. Three species groups have been segregated into three newly established separate genera: Crepidifolium, Sonchella, and Tibetoseris. Crepidifolium includes Babcock and Stebbins’s (Publ. Carnegie Inst. Washington 484: 25. 1937) single species of their (not validly published) "Y. sect. Crepidopsis," meanwhile divided into three separate species. Most recent molecular phylogenetic analyses of the Crepidinae by J. W. Zhang et al. (in prep.) on the one hand confirmed that Crepidifolium is not part of Youngia, but on the other hand revealed that it is actually nested within Crepidiastrum, see there. Sonchella unites Y. stenoma of Babcock and Stebbins’s (not validly published) "Y. sect. Stenophytum" and a second species formerly treated as Prenanthes angustifolia or Crepis pratensis. This genus has been confirmed in the molecular phylogenetic analyses by J. W. Zhang et al. (in prep.) as independent and is treated as such here. Tibetoseris included the five species of Babcock and Stebbins’s (not validly published) "Y. sect. Desiphyllum" and a few later additions from China. Tibetoseris was most recently recircumscribed by D. Maity and Maiti (Compositae Newslett. 48: 22-42. 2010) to include only T. depressa, while the other species, considered from morphology as unrelated, were segregated into the newly established genus Pseudoyoungia. While their assumption of Tibetoseris being diphyletic has been confirmed in the molecular phylogenetic analyses by J. W. Zhang et al. (in prep.), the exclusion of the species united in Pseudoyoungia from Youngia has not; they appear clearly nested in Youngia. Pseudoyoungia is here therefore sunk in the synonymy of Youngia. Finally, examination of the type material of Y. blinii, considered as an unusual and isolated species of Youngia since its inclusion by Babcock and Stebbins (Univ. Calif. Publ. Bot 18(11): 227-229. 1943, as Y. setigera), revealed that it is grossly misplaced in Youngia but conveniently fits into Dubyaea, where it is transferred in the present treatment. The genus is still in need of a revision at species level. Many species are known from few collections only and their justifications need to be confirmed by a thorough study of character variation on the basis of more material. The current treatment should be used with critical caution.

About 30 species: E Asia; 28 species (22 endemic) in China.

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


 

IBSC @ efloras.org
Browse by
Family
Genera
Search by name

Specimen Search

People @ IBSC

 

 

 |  eFlora Home |  People Search  |  Help  |  ActKey  |  Hu Cards  |  Glossary  |