Lobelia (sect. Rhynchopetalum)

Key to the South American species of Lobelia sect. Rhynchopetalum 1. Corolla shorter than 2.8 cm long, unilabiate, all lobes connate at the apex ..................................................................................... 2 − Corolla longer than 3 cm long, sub-bilabiate or unilabiate, all lobes free at the apex ..................................................................... 3 2. Stem and leaves glabrescent; bracts deflexed; seeds winged, wing equal in size to the seminiferous nucleus ...... Lobelia exaltata − Stem and leaves densely tomentose; bracts erect; seeds not or slightly winged, wing when present narrower than the seminiferous nucleus ..................................................................................................................................................................... Lobelia hassleri 3. Leaves glabrous on both surfaces ..................................................................................................................................................... 4 − Leaves tomentose or pubescent at least on the abaxial surface ........................................................................................................ 9 4. Flowers in shades of white and/or pink, different shades along the flower and/or the inflorescence; corolla unilabiate; lateral lobes of the corolla 3 cm long or longer, convolute ........................................................................................................ Lobelia capixaba − Flowers in shades of lilac, purple, or vibrant pink, single tone along the flower and the inflorescence; corolla sub-bilabiate; lateral lobes of the corolla up to 2.5 cm long, non-convolute .................................................................................................................... 5 5. Leaf blade ovate to suborbicular, margin crenulate to serrate; bracts ovate to suborbicular; seeds not winged ................................. .......................................................................................................................................................................... Lobelia santos-limae − Leaf blade linear, lanceolate, or oblong, margin entire, denticulate or dentate; bracts linear to lanceolate; seeds winged ............. 6 6. Corolla tomentose; bracteoles conspicuous, ca. 10 mm long, margin ciliate ........................................................ Lobelia langeana − Corolla glabrous; bracteoles inconspicuous, ca. 1 mm long, margin entire ..................................................................................... 7 7. Leaf margin doubly serrate, teeth ca. 1 mm long; inflorescence lax; pedicel 1.9−3.2 cm long ........................ Lobelia glazioviana − Leaf margin finely denticulate, denticles up to 0.5 mm long; inflorescence congested; pedicel up to 1 cm long ........................... 8 8. Latex white; bracts conspicuous, erect; pedicel winged; lobes of the corolla with acute apex, not elongated ...... Lobelia fistulosa − Latex yellowish; bracts inconspicuous, deflexed; pedicel not winged; lobes of the corolla with filiform, elongated apex ............... .............................................................................................................................................................................. Lobelia hilaireana 9. Leaves tomentose on both surfaces; seeds with a wing smaller than the seminiferous nucleus ........................ Lobelia thapsoidea − Leaves pubescent only on the abaxial surface; seeds with a wing larger than the seminiferous nucleus ...................................... 10 10. Leaves covered by yellowish tomentum, leaf margin entire to denticulate, teeth unhardened; corolla and ovary densely tomentose ............................................................................................................................................................ Lobelia brasiliensis − Leaves covered by whitish tomentum, leaf margin dentate, teeth hardened; corolla and ovary glabrous ......... Lobelia organensis