Youngia japonica (L.) DC. 黃鵪菜

Youngia japonica (L.) DC. 黃鵪菜 is a species of the family Asteraceae 菊科, with three subspecies:

• Youngia japonica (L.) DC. subsp. japonica黃鵪菜

• Youngia japonica (L.) DC. subsp. monticola Koh Nakam. & C.I Peng 山間黃鵪菜

• Youngia japonica (L.) DC. subsp. formosana (Hayata) Kitam. 台灣黃鵪菜

Herbs usually 10-60 cm tall, annual or biennial. Stems solitary or branched from base, middle, or only apically. Inflorescence axes glabrous, slightly puberulous or densely puberulous at base. Taproot light brown. Radical leaves, basal, ± oblanceolate, lyrately pinnatipartite or pinnatisect. Glabrous or somewhat hairy. Flower yellow. Heads less than 15 mm wide. Involucre 4–6 mm long. Fusiform achene brown or reddish brown to dark purplish brown, 1.5-2.5 mm long, with white pappus, 2.5-3.5 mm long.

Native in Asia. Among the three subspecies, Youngia japonica (L.) DC.  subsp. japonica is invasive worldwide. It prefers moist conditions and is highly adaptable to many growing conditions. Each subspecies (as the order above) adapts to different habitats respectively: lowland regions with a broad range of environmental conditions, mountain ranges, and littoral, raised coral reefs. Wind dispersal.

Identification of the subspecies used to be taxonomically confusing. Nakamura et al. (2013) corrected the confusions of identity and synonymy of Youngia in Taiwan. They described a new subspecies Youngia japonica (L.) DC. subsp. monticola Koh Nakam. & C.I Peng 山間黃鵪菜 and clarifying the identity of Youngia japonica (L.) DC. subsp. formosana (Hayata) Kitam. 台灣黃鵪菜, which is the plant that I am going to introduce next.