Thelionema umbellatum, the lemon flax lily is a species of perennial herb, native to Australia.

Growing up to 40 cm high, the lily-like flowers are white with yellow stamens.

The species occurs in Tasmania, Victoria and New South Wales.

Found south of Swansea, New South Wales on shallow or peat based soils from coastal areas up to 1,000 metres above sea level.

Appearing in his Prodromus Florae Novae Hollandiae et Insulae Van Diemen in 1810.