Morphological characters distinguishing the subgenera in Monnina

Character   Subg. Monnina   Subg. Pterocarya   Subg. Monninopsis
Habit   Shrub   Mainly herb   Herb
Extra-floral nectary   Absent   Present/Absent    Absent
Inflorescence   Condensed   Lax   Sublax
Flower color   Dark purple   Mainly light purple    Pinkish
Posterior sepals   Free or connate   Free   Connate
Posterior petal   Trilobed   Trilobed   Tricleft
Staminal sheath   Apically free to connate   Apically free to connate   Apically connate
Style   Thick, without lobes   Thick with lobes   Thin, without lobes
Fruit   Mainly drupe   Mainly samara   Drupe or samara
Distribution   Endemic to Andes   Low Andes/Southern S.A.    Endemic to northern Brazil