Erigeron species, 1753

Cerros-Tlatilpa, Rosa, Miguel-Vázquez, Mónica I., Caspeta-Mandujano, Juan M., Méndez-Cano, Rafael & Guerrero, Jose A., 2023, Erigeron morelensis (Asteraceae): a rediscovery after more than 120 years of a microendemic and threatened species in central Mexico, Phytotaxa 587 (3), pp. 211-217 : 215

Key to Erigeron species from E. sect. Erigeridium (based on Nesom 2008)

1. Stems branched, corymbiform, (1–)4–20(–25) capitula; plants distributed in SE US.......................................................... E. vernus

- Stems not branched, monocephalous; plants distributed in Mexico..................................................................................................2

2. Involucre densely white-villous; phyllaries with glandular trichomes........................................................................ E. hintoniorum

- Involucre sparsely white-villous; phyllaries sparsely pubescent without glandular trichomes .........................................................3

3. Stolons present; phyllaries lanceolate, apex acute to acuminate; ray florets 60–90 ...................................................... E. morelensis

- Stolons absent; phyllaries linear-lanceolate to elliptic-lanceolate, apex acuminate; ray florets 70–135 ...........................................4

4. Leaves spatulate-oblong, obtuse; phyllaries linear-lanceolate; ray florets 80–90............................................................... E. palmeri

- Leaves narrowly to broadly oblanceolate to spatulate; phyllaries lanceolate to elliptic-lanceolate; ray florets 70–135 ...... E. wellsii