What is "polystemma"

Polystemma is a genus of flowering plants of the family Apocynaceae first described as a genus in 1844. It is native to Mexico and Central America.

1. Polystemma guatemalense (Schltr.) W.D.Stevens - from Nayarit to Costa Rica
2. Polystemma mirandae Lozada-Pérez - Guerrero, Oaxaca, Puebla
3. Polystemma viridiflora Decne. - Michoacán, Veracruz, Oaxaca, Chiapas