Streptocarpus, Lindley, 1828

Christenhusz, Maarten J. M., 2012, On African violets and Cape primroses-towards a monophyletic Streptocarpus (Gesneriaceae), Phytotaxa 46, pp. 3-9 : 4

Key to the tropical East African species of Streptocarpus subgenus Streptocarpella

1. Plants acaulescent, all leaves sprouting directly from the soil surface, the stems underground with no aboveground branching; leaves solitary or in a rosette, spirally arranged; fruits always conspicuously twisted ................................ .............................................................................................................................................. S. subgenus Streptocarpus

-. Plants caulescent, leaves sprouting from aboveground stems, sometimes the internodes reduced and the plant appearing (sub-)rosulate; leaves opposite or alternate; fruits twisted or not.................2. S. subgenus Streptocarpella

2. Leaves alternate ............................................................................................................................................................ 3

-. Leaves opposite (sometimes becoming alternate due to differential growth) ............................................................. 6

3. Leaves subsessile; lateral veins scalariform .................................................................................................. S. bullatus

-. Leaves petiolate; lateral veins ascending...................................................................................................................... 4

4. Leaf apices acute to short-acuminate; plants subscandent ..................................................................... S. subscandens

-. Leaf apices rounded to obtuse; plants subrosulate or creeping .................................................................................... 5

5. Plants creeping; petiole more than half as long as the length of the blade ........................................ S. heckmannianus

-. Plants subrosulate; petiole less than half the length of the blade ...................................................................... S. albus

6. Corolla tube up to 3 mm long, shorter than the upper lobe; anthers yellow, always exserted ...................................... ................................................................................................................................................ 7. (formerly Saintpaulia )

-. Corolla tube 4–40 mm long, longer than the upper lobe; anthers not yellow, usually included in the tube .............. 12

7. Leaf blades glabrous above .................................................................................................................... S. inconspicuus

-. Leaf blades pubescent above ........................................................................................................................................ 8 8. Upper corolla lobes clearly darker blue to violet, the lower lobes near white; leaf blades usually less than 4 cm long ..................................................................................................................................................................................... 9