Perennial clump-forming stoloniferous herb to about 30 cm. Leaves sessile, broadly ovate, mottled. Inflorescence 1-flowered, terminal. Flowers narrow cup-shaped, erect, petals erect; spring to summer. Sepals to 4 cm long, narrowly ovoid, greenish-purple. Petals to 4.5 cm long, dark purple-brown, narrowly ovoid. Filaments purple; anthers purple. Fruit angular or winged.

T. grandiflorum (Michx.) Salisb., White Trillium (Large-flowered Trillium), from Eastern N America is a perennial clump-forming rhizomatous herb to about 45 cm. Leaves more or less sessile, broadly ovate, green. Inflorescence 1-flowered, terminal. Flowers bowl-shaped, erect, petals reflexed to recurved; spring to summer. Sepals to 5 cm long, leaf-like, green. Petals to 9 cm long, white fading to pink, broadly ovate. Filaments green; anthers yellow. Fruit deep red.

T. rivale Wats. from Oregon and California is a perennial clump-forming rhizomatous herb to about 25 cm. Leaves with a 5-20 mm leaf stalk, narrow ovate to ovate, green. Inflorescence 1-flowered, terminal. Flowers bowl-shaped, erect, petals spreading; spring. Sepals to 1.6 cm long, leaf-like, green. Petals to 2.5 cm long, white to pink, with basal pink-purple markings, broadly ovate. Filaments white; anthers yellow. Fruit brown.

NE USA.

Source: Conran, J. (2005). Trilliaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 5. Flowering plants. Monocotyledons. The identification of garden and cultivated plants. University of New South Wales Press.