Youngia

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Distribution

Africa: Comoros (Comorosintroduced); KwaZulu-Natal (KwaZulu-Natalintroduced); Madagascar (Madagascarintroduced); Mauritius (Mauritiusintroduced); Rodrigues (Rodriguesintroduced); Réunion (Réunionintroduced); Seychelles (Seychellesintroduced) Asia-Temperate: Afghanistan (Afghanistannative); China North-Central (Beijingnative, Gansunative, Hebeinative, Shaanxinative, Shandongnative, Shanxinative: presence questionable); China South-Central (Chongqingnative, Guizhounative, Hubeinative, Sichuannative, Yunnannative); China Southeast (Anhuinative, Fujiannative, Guangdongnative, Guangxinative, Henannative, Hunannative, Jiangsunative, Jiangxinative, Zhejiangnative); Hainan (Hainannative); Japan (Hokkaidonative, Honshunative, Kyushunative, Shikokunative); Korea (North Koreanative, South Koreanative); Nansei-shoto (Nansei-shotonative); Ogasawara-shoto (Ogasawara-shotonative: doubtfully native); Qinghai (Qinghainative); Taiwan (Taiwannative); Tibet (Tibetnative) Asia-Tropical: Assam (Assamnative, Meghalayanative); Bangladesh (Bangladeshnative); Borneo (Sabahnative); Cambodia (Cambodianative); East Himalaya (Bhutannative, Darjilingnative, Sikkimnative); India (Biharnative, Delhinative, Haryananative, Keralanative, Punjabnative, Tamil Nadunative, Uttar Pradeshnative); Jawa (Jawaintroduced); Laos (Laosnative); Malaya (Peninsular Malaysianative); Myanmar (Myanmarnative); Nepal (Nepalnative); New Guinea (Irian Jayanative, Papua New Guineanative); Pakistan (Pakistannative); Philippines (Philippinesnative); Sri Lanka (Sri Lankanative); Thailand (Thailandnative); Vietnam (Vietnamnative); West Himalaya (Himachal Pradeshnative, Jammu-Kashmirnative, Uttaranchalnative) Australasia: New South Wales (New South Walesnative); Queensland (Queenslandnative) Northern America: Alabama (Alabamaintroduced); Arkansas (Arkansasintroduced); District of Columbia (District of Columbiaintroduced); Florida (Floridaintroduced); Georgia, U.S.A. (Georgia, U.S.A.introduced); Kentucky (Kentuckyintroduced); Louisiana (Louisianaintroduced); Maryland (Marylandintroduced); Mississippi (Mississippiintroduced); New York (New Yorkintroduced); North Carolina (North Carolinaintroduced); Pennsylvania (Pennsylvaniaintroduced); South Carolina (South Carolinaintroduced); Tennessee (Tennesseeintroduced); Texas (Texasintroduced); Virginia (Virginiaintroduced) Pacific: Fiji (Fijiintroduced); Hawaii (Hawaiian Is.introduced); New Caledonia (New Caledoniaintroduced) Southern America: Argentina Northeast (Entre Ríosintroduced); Argentina Northwest (Tucumanintroduced); Bahamas (Bahamasintroduced); Cayman Is. (Cayman Is.introduced); Cuba (Cubaintroduced); Dominican Republic (Dominican Republicintroduced); Haiti (Haitiintroduced, Navassa I.introduced); Hondurasintroduced; Jamaica (Jamaicaintroduced); Leeward Is. (Virgin Is.introduced); Netherlands Antillesintroduced; Puerto Rico (Puerto Ricointroduced); Venezuela (Venezuelaintroduced); Windward Is. (Barbadosintroduced, Dominicaintroduced)

Description

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.

from: Shih C. & Kilian N. in Wu Z. Y. & al. (ed.), Flora of China 20–21: 252. 2011, Beijing & St Louis.

Common names

Chinese (China): 黄鹌菜属 huang an cai shuA; Vietnamese (Vietnam): Cải giảB

Etymology

The name of the genus honours, according two Cassini, two Englishman, a poet and a physician ("qui rappelle celui de deux Anglais célèbres, l'un comme poète, l'autre comme physicien", p. 89). Very likely these are the poet and author Edward Young (1683–1765) and the ophthalmologist, physicist, linguist and egyptologist Thomas Young (1773–1829).C

Chromosome numbers

Diploids and, more rarely, tetraploids, x = 8.D

Systematics

The circumscription of Youngia as established by Babcock & Stebbins (1937) was changed by Sennikov & Illarionova (2008), based, in particular, on karpological analyses. Three of the species groups recognised by Babcock & Stebbins (1937) were segregated into three newly established separate genera: Crepidifolium, Sonchella and Tibetoseris (Sennikov & Illarionova 2008).

Crepidifolium includes the single species of "Y. sect. Crepidopsis” (not validly published) of Babcock & Stebbins (1937), which meanwhile has been divided into three separate species. Molecular phylogenetic analyses by Peng & al. (2014) confirmed that Crepidifolium is not part of Youngia, and that it is actually a congener of Crepidiastrum, as treated by Shih & Kilian (in Shih & al. 2011) and had been proposed earlier by Sennikov (1997: 115).

Sonchella unites Youngia stenoma of "Y. sect. Stenophytum” (not validly published) of Babcock & Stebbins (1937) and a second species formerly treated as Prenanthes angustifolia or Crepis pratensis. This genus has been confirmed in a molecular phylogenetic analyses by J. W. Zhang & al. (unpubl.) as independent and rather remote of Youngia, being part of a larger clade also including Dubyaea, Hololeion, Nabalus, Soroseris and Syncalathium. Sonchella has therefore been maintained by Shih & Kilian (in Shih & al. 2011).

Tibetoseris, finally, included the five species of "Y. sect. Desiphyllum” (not validly published) of Babcock & Stebbins (1937) and a few later additions from China. Based on morphological studies, Tibetoseris was most recently narrowed down by Maity & Maiti (2010) to include only T. depressa. The other species were segregated into the newly established genus Pseudoyoungia (Maity & Maiti 2010). Maity & Maiti's (2010) assumption that Tibetoseris is diphyletic has been corroborated by the molecular phylogenetic analyses of J. W. Zhang & al. (unpubl.). The segregation from Youngia of the species united in Pseudoyoungia has, however, not been confirmed by the molecular analysis. In contrast, as Deng & al. (2014) have shown, they are clearly nested in Youngia. Pseudoyoungia is therefore to be sunk in the synonymy of Youngia as done by Shih & Kilian (in Shih & al. 2011). J. W. Zhang & al. (unpubl.), moreover, found that the only remaining species of Tibetoseris is actually nested in the clade of Soroseris.

According to the circumscription by Shih & Kilian (in Shih & al. 2011) and including recent additions and adjustments by Peng & al. (2014), Deng & al. (2014) and Peng & al. (2015), Youngia comprises some 34 species of E and S Asia, with a centre of diversity in China, where most of its species are endemic.

Another interesting results of the nrITS phylogeny by Deng & al. (2014) regards the genus Lapsanastrum: a member of that genus included in their analysis is deeply nested within Youngia, indicating this lineage to have been evolved within Youngia.

References


Babcock E. B & Stebbins G. L. 1937: The genus Youngia. – Publ. Carnegie Inst. Washington 484.

Deng T., Zhang J.-W., Zhu X.-X., Zhang D.-G., Nie Z.-L. & Sun H. 2014: Youngia zhengyiana (Asteraceae, Crepidinae), a new species from south China, with notes on the systematics of Youngia inferred from morphology and nrITS phylogeny. – Phytotaxa 170: 259–268. // ➪ //

Maity D. & Maiti G. G. 2010: Taxonomic delimitation of the genus Tibetoseris Sennikov and the new genus Pseudoyoungia of the Compositae-Cichorieae from Eastern Himalaya. – Compositae Newslett. 48: 22–42.

Peng Y.-L., Ju W.-B., Gao X.-F. & Gao Y.-D. 2015: Youngia purpimea (Asteraceae), a new species from Sichuan, China. – Phytotaxa 236: 191–195. // ➪ //

Peng Y.-L., Zhang Y., Gao X.-F., Tong L.-J, Li L., Li R.-Y., Zhu Z.-M. & Xian J.-R. 2014: A phylogenetic analysis and new delimitation of Crepidiastrum (Asteraceae, tribe Cichorieae). – Phytotaxa 159: 241–255. // ➪ //

Sennikov A. N. 1997: Kriticheskie zametki o vidakh podtrib Lactucinae i Crepidinae (Asteraceae, Lactuceae) Mongolii, Kitaya i V'etnama [Critical notes on the species of the subtribes Lactucinae and Crepidinae (Asteraceae, Lactuceae) from Mongolia, China and Vietnam]. – Bot Zhurn. 82(5): 110–117.

Sennikov A. N. & Illarionova I. D. 2008 ["2007"]: Generic delimitation of the subtribe Ixeridinae newly segregated from Crepidiinae (Asteraceae-Lactuceae). – Komarovia 5: 57–115.

Shih C., Ge X. J.; Kilian N., Kirschner J., Štěpánek J., Sukhorukov A. P., Mavrodiev E. V. & Gottschlich G. 2011: Cichorieae. – Pp. 195–353 in: Wu Z. Y., Raven P. H. & Hong D. Y. (ed.), Flora of China 20–21. Asteraceae. – Beijing: Science Press & St Louis: Missouri Botanical Garden.

Bibliography

A. Wu & al., Flora of China 20-21. 2011
B. Lê Kim Biên, Thục-vât-chí-Viêt-Nam / Flora of Vietnam 7. Họ cúc / Asteraceae. 2007
C. Burkhardt L., About some eponyms in Taxonomic Literature (TL-2) in Taxon 65. 2016
D. Watanabe K., Index to chromosome numbers in Asteraceae.