Print Fact SheetYoungia japonica

Taxonomy

Youngia japonica (L.) DC., Prodr. 7(1): 194, 1838.

Common synonyms

Prenanthes japonica L. Mant. Pl. 107. 1767.

Common name

Asiatic hawksbeard, Japanese hawkweed

Description

Propagule or dispersal unit is the fruit with pappus. Fertile part 1.25-2 mm long, 0.2-0.5 mm wide, in side view widest in lower part (ovoid) or widest in the middle, conspicuously curved, the upper (apical) end narrowing, in cross-section flattened, basal scar (carpopodium) inconspicuous and undifferentiated, central, beak (=thinner sterile stalk between seed and pappus) absent, wings absent, fruit surface light brown or straw or dark brown, smooth (except at cellular level), with simple straight hairs, thickened margin absent, longitudinal ribs present, 10-13, their surfaces smooth, with simple straight hairs.

Pappus type bristles / hairs, pappus elements all +/- similar, up to 2-3.5 mm long, in one row, pappus elements numerous, persistent or elements falling off individually (by misinterpretation), the individual bristles rough / serrated (barbellate), +/- equal width along length, white / translucent.

Notes: Hairs on the fruit surface are very short and conical. Individual pappus bristles easily break off at the base and may consequently be missing.

Ecology

Biennial herb, fruits wind-dispersed. Temperate to tropical regions, requires moist soil. Naturally along creeks or rainforest margins or in other sheltered positions, but as a weed also on wastelands, agricultural areas, lawns, orchards, and roadsides.

Native range

Widespread across southern, eastern and south-eastern Asia to Australia.

Introduced range

United States, Mexico, Caribbean, Central America, Colombia, Venezuela, Brazil, Madagascar.

Past interceptions (Australia): origins

Thailand.

Past interceptions (Australia): commodities

New vehicles.