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Support the Flora of the Southeastern US

2024 has been a banner year for making the best flora we can imagine. We've created:
With financial support from people like you, we are aiming even higher in 2025. Together we can accomplish all this: Vote on our 2025 priorities
  • Add Global Conservation Ranks (GRanks) vote
  • Professional graphic keys (polyclaves) to individual families/genera vote
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We've set a goal of recruiting 200 ongoing supporters to donate $15 or more each month in 2025. Please help us reach this goal and make next year's flora even better:

Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.

Key to Apocynaceae

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1 Plant erect or trailing (but not twining), herbaceous or woody.
  2 Plant a woody shrub, subshrub, or trailing woody vine.
    3 Leaves alternate.
      4 Fruit follicles; [waif]
      4 Fruit drupes; [native and non-native]
        5 Leaves lanceolate; corolla white, salverform, < 1 cm long; fruit white; [rare native, s. FL]
        5 Leaves linear; corolla yellow, funnelform, ca. 5 cm long; fruit green to brown; [non-native, s. TX and FL peninsula]
    3 Leaves opposite or whorled.
          6 Plants armed, the stems with stout, bifurcated spines
          6 Plants unarmed, the stems without spines.
             7 Plant rhizomatous, suffrutescent, < 4 dm tall; leaves narrowly to broadly ovate; flowers blue, lavender, or white
             7 Plant erect, > 4 dm tall; leaves either lanceolate or elliptic (or oblanceolate in Allamanda cathartica); flowers yellow, white, pink, or red.
               8 Flowers white, pink, or red; shrub 10-40 dm tall, much branched from the base; [commonly cultivated in our area (and sometimes persistent), particularly near the coast; NC s. to FL, w. to TX]
               8 Flowers yellow; plants erect subshrubs 4-12 dm tall (Angadenia berteroi) or trailing to erect woody vines 0-20 m tall (Allamanda cathartica); [FL].
                 9 Leaves oblanceolate, 15-40 mm wide, mostly in whorls of 3-4; plants larger trailing or erect woody vines; follicles rounded and spiny; [non-native of disturbed habitats, c. and s. FL]
                 9 Leaves narrowly elliptic to oblong, 2.5-10 mm wide, leaves opposite; plants smaller subshrubs; follicles smooth; [native of pine rocklands and marl prairies, s. FL]
  2 Plant an herb or trailing herbaceous vine.
                   10 Flowers with conspicuous or less conspicuous corona; follicles not paired; seeds with coma present.
                     11 Plant either an erect herb or a decumbent herb with stiff, thick stems (> 4 mm in diameter); leaves various, but not both petiolate and heart-shaped
                     11 Plant a trailing herbaceous vine with weak, thin stems (<2 mm in diameter); leaves petiolate and heart-shaped, 2-4 cm long
                   10 Flowers lacking corona; follicles paired (occasionally single by abortion); seeds with coma absent (Catharanthus, Amsonia) or present (Apocynum).
                       12 Leaves alternate (rarely a few on a plant subopposite)
                          13 Flower < 8 mm across; paired follicles pendent, 10-22 cm long; seeds with coma; mature plants normally > 7 dm tall
                          13 Flower > 20 mm across; paired follicles erect, 1.5-2.5 cm long; seeds lacking coma; mature plants 2-6 dm tall
                            14 Leaves conspicuously cordate at base (or subcordate to truncate in Vinceotoxicum), ovate to broadly lanceolate, ca. 1-4× as long as wide.
                                  17 Flowers maroon-colored; leaf bases usually truncate or rounded (occasionally subcordate)
                                    18 Stems glabrous to puberulent (the hairs sometimes curved), but lacking glandular-capitate hairs; petals white; gynostegial corona > ¾ as long as the corolla lobes.
                                       19 Corolla lobes uniformly whitish or cream colored, unicolored; MORE
                                    18 Stem pubescence a mix of eglandular and glandular-capitate hairs; petals purple-black, brown, yellow, yellow-green, cream, or maroon (white in Matelea baldwyniana); gynostegial corona < ½ as long as the corolla lobes.
                                               23 Follicles smooth, with or without apparent angles but not studded.
                                                    25 Stems with nodes conspicuously pubescent, often with curved trichomes throughout; MORE
                            14 Leaves not cordate at base (cuneate, rounded, or truncate; occasionally subcordate but this not predominant); leaves ovate, lanceolate, or linear, ca. 1.5-10x as long as wide.
                                                            29 Stems herbaceous; corollas maroon-colored throughout, without green corolla margins; [widespread non-natives, ne. US]
                                                          28 Flowers primarily white, whitish-green, creamy yellow, pure yellow, or light pink.
                                                                 31 Corolla lobes 1.5-3.5 mm long; leaves linear to ovate (but never hastate); [native of rocklands, woodlands, hammocks, pastures; TX and FL]