1. Arrow-leaved Thelypody: Thelypodium eucosmum - Stem leaves with heart-shaped and sometims clasping bases, typically without distinct petioles. Basal leaves short petiolate with entire to sinuate or dentate margins. Petals lilac-purple, 6-8 mm long. Fruits arcuate-spreading, 3-4.5 cm long and 1-2 mm wide. with stems from 1-5 mm long.
2. Weak Thelypody: Thelypodium flexuosum - Stem leaves without distinct petioles and with basal lobes that clasp the stem. The leaves have entire margins. The flowers are lavender to white. The fruits are less than 3.5 cm long with stalks less than 1 mm long.
3. Howell's Thelypody: Thelypodium howellii - Stem leaves sessile and auriculate. Basal leaves lyratelylobed, 2-4 cm long and more or less hirsute. Flowers greenish-white to purple. Fruits ascending to erect, 2-4 cm long and about 1 mm wide on pedicels about 0.5 mm long.
4. Entire-leaved Thelypody: Thelypodium integrifolium ssp. complanatum - Stem leaves without distinct petioles and lacking basal lobes that clasp the stem. The leaves have entire margins. The flowers are lavender. The fruits are less than 3.5 cm long with stalks less than 1 mm long.
5. Thick-leaved Thelypody: Thelypodium laciniatum - Stem leaves with distinct petioles. Lower stem leaves (and often above) toothed or lobed. The petals are linear and not wide at the tip. Fruits are over 3.5 cm long on stalks at least 1 mm long, and are spreading to drooping. The pedicels are straight and spreading.
6. Fine-leaf Thelypody: Thelypodium milleflorum - Stem leaves with distinct petioles. Lower stem leaves (and often above) toothed or lobed. Petals are wide at the tip. Fruits are over 3.5 cm long on pedicels at least 1 mm long, and are ascending to erect. The pedicels are sharply curved upwards in fruit.
7. Slender Thelypody: Thelypodium sagittatum - Stem leaves not petiolate. Basal leaves petiolate with entire, sinuate or toothed margins. Petals light to deep violet-ppurple, 10-16 mm long. Fruits straight, ascending close to the stem, 2.5-4 cm long and 1-2 mm wide on stalks about 0.5 mm long.