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Key to Odontostephana

Apocynaceae

Odontostephana

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1 Corolla primarily maroon (species suffused with maroon and also green/yellow keyed under both couplets).
  2 Corolla conspicuously reticulate on both surfaces (the primary corolla color usually yellow-green but often maroon tinged);
  2 Corolla not reticulate (or only faintly so, these reticulations inconspicuous if at all evident).
    3 Corolla lobes plane or reflexed (held flat or curved downward towards the base of the flower).
      4 Corona lobes each bearing 2 lobes (projections); corolla lobes 4-15 mm long; inflorescences with 3-30+ flowers; [DE and MD south to s. GA and westward, not known from FL]
      4 Corona lobes each bearing 4 teeth (projections); corolla lobes 3-7 mm long; inflorescences with 3-10 flowers; [nearly endemic to FL, rare in sw GA]
    3 Corolla lobes ascending (held upright, away from the base of the flower).
        5 {XXXX}; [west of the MS river]
          6 Upper (adaxial) surface of the corolla lobes glabrous, the lobes 7-18 mm long; pedicels 10-25 mm long; [scattered from KS and MO south through OK and AR to TX and LA]
          6 Upper (adaxial) surface of the corolla lobes usually hirtellous (sometimes glabrate), the lobes 3.2-7.5 mm long; pedicels 6-13 mm long; [AR and TX, primarily of the Piney Woods region of e. TX]
        5 {YYYY}; [east of the MS river]
             7 Corona 2-3 mm in diameter; corolla variously maroon, brown, dark purple or yellowish-green to yellowish-maroon, the lobes 4-15 mm long; inflorescences with 3-30+ flowers
             7 Corona 3-5 mm in diameter; corolla primarily reddish-purple to reddish-brown, the lobes 8-16 mm long; inflorescences with 5-15 (-20) flowers
1 Corolla primarily green, yellow, or often a combination of the two (e.g., greenish-yellow, rarely white or cream-colored as in M. baldwiniana; flowers suffused with both maroon and green/yellow keyed under both couplets).
               8 Corolla lobes plane or reflexed (held flat or curved downwards towards the pedicels).
                 9 Corolla conspicuously reticulate (sometimes concentrated towards the tips of the lobes but the venation still distinct)
                   10 Corolla lobes 3-5 mm long; [absent from e. TX, instead primarily c. TX west and southward]
                     11 Corollas campanulate-rotate (the flowers, viewed from the side, with a slightly more evident cup-shape at the base), the lobes fused for at least 1/4th of their length, often with some level of overlap where the lobes converge
                     11 Corollas rotate (the flowers, viewed from the side, held flat), the lobes distinct (or nearly so) to their bases, the point of lobe convergence usually lacking any notable overlap
                   10 Corolla lobes 4-15 mm long; [primarily occuring e. of MS river (occurring sparingly west of the river, merely approaching extreme e. TX)
                       12 Corolla lobes ovate; inflorescence 1-5-flowered (rarely more, averaging 4-5 per inflorescence), pedicels 5-15 mm long; follicles densely muricate (studded), ca. 5-8 cm long; [rare, known from the tri-state area of se. AL, sw. GA and FL panhandle)
                       12 Corolla lobes oblong; inflorescence 3-40 flowered (averaging 9-19 per inflorescence), pedicels 3-25 mm long; follicles sparsely to moderately muricate (studded); [collectively widespread, including the above mentioned tri-state region].
                          13 Paired corona appendage length always longer than the alternating corona lobes, apical anther appendages bright white with yellow to maroon-colored patch at base
                          13 Paired corona appendage length ca. as long as alternating corona lobes, apical anther appendages bright white with green patch at the base
                 9 Corolla not reticulate (or only faintly so, these reticulations inconspicuous if evident at all).
                            14 Upper (adaxial) corolla lobes glabrous; [GA and FL]
                              15 Flowers (including both corolla and corona) white or cream-colored, the corolla lobes often twisted
                              15 Corolla green, yellow, or often a combination of the two (e.g., greenish-yellow, sometimes suffused with maroon), corona variously colored (if sometimes cream-colored then the corolla differing in color); corolla lobes not or slightly twisted.
                                16 Corolla conspicuously reticulate (on yellow-flowered forms); [primarily east of the MS river]
                                16 Corolla not reticulate (or only faintly so, these reticulations inconspicuous if evident at all); [west of the MS river only].
                                  17 Pedicels 10-25 mm long; corolla lobes 7-18 mm long; [S. IL, c. MO, and se. KS, south to LA and e. TX]
                                  17 Pedicels 6-13 mm long; corolla lobes 3.2-7.5 mm long; [nearly endemic to the Piney Woods ecoregion of e. TX]