Periglossum

Bester, Stoffel P. & Nicholas, Ashley, 2016, Periglossum podoptyches (Apocynaceae-Asclepiadoideae), a new species from KwaZulu-Natal province, South Africa, Phytotaxa 282 (1), pp. 28-36 : 35

Key to the species in Periglossum expanded from Brown (1907) and Nicholas (1999):

1. Blade of the staminal corona lobes sagittate-ovate, ± as long as the stalk; interstaminal lobes filiform, 1.5–4.0 mm long ............... ................................................................................................................................................................ Periglossum angustifolium

– Blade of the staminal corona lobes oblong or lanceolate oblong to elliptic-oblong, ca. 2–2.5 times as long as the stalk; interstaminal lobes to 2.0 mm long ....................................................................................................................................................................... 2

2. Interstaminal corona lobes filiform, ca. 2 mm long ............................................................................ Periglossum mossambicense

– Interstaminal corona lobes rudimentary, ≤ 2 mm long ..................................................................................................................... 3

3. Ventral side of staminal corona lobe solid and without keels, stalk of interstaminal corona lobe with flaps of tissue at their base .. ................................................................................................................................................................... Periglossum podoptyches

– Ventral side of staminal corona lobe with keels, stalk of staminal corona lobe without any flaps of tissue at their base ............... 4

4. Leaves suberect; staminal corona lobes with stout, longitudinal double-keel on upper half of blade and two slender contiguous keels below ............................................................................................................................................ Periglossum kassnerianum

– Leaves spreading; staminal corona lobe blade thickened at the apex without any longitudinal keel ........... Periglossum mackenii