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Key to Rubiaceae

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1 Trees, shrubs, or woody vines.
  2 Prostrate or climbing woody vines (lianas), or sprawling shrubs.
    3 Leaf bases cordate, rounded, or truncate; leaves usually cordate, ovate, or deltoid shaped (occasionally hastate or broadly elliptic); corolla pale lilac colored; [non-native, se. US including FL; tribe Paederieae]
    3 Leaf bases cuneate to rounded but not cordate; leaves oblanceolate, lanceolate or linear; corolla white or yellow; [native, FL].
      4 Flowers and fruit sessile or subsessile; fruit yellow
      4 Flowers and fruit borne on pedicels or peduncles; fruit white
  2 Shrub or tree, plants upright.
        5 Inflorescence spherical or globular, in a tight round head; [collectively widespread]
          6 Fruits dry, dehiscent; [subfamily Cinchonoideae; tribe Naucleeae]
          6 Fruits fleshy, indehiscent; [subfamily Rubioideae; tribe Morindeae]
        5 Inflorescence cymose, thyrsoid, or corymbose (the inflorescence more open, not round and compact); [Coastal Plain, from s. SC southward].
             7 Plants with paired spines.
               8 Corolla lobes 4; leaves to ca. 1 cm long; fruit ca. 5 mm long
               8 Corolla lobes 5; leaves ca. 2-5 cm long ; fruit ca. 10 mm long
             7 Plants unarmed, not bearing spines or thorns.
                 9 Flowers orange-red; leaves usually whorled; [subfamily Cinchonoideae; tribe Hamelieae]
                 9 Flowers white, green, or maroon; leaves opposite.
image of plant
Show caption*© Scott Ward
                   10 Leaves linear, revolute, and strongly congested; [FL keys southward]
                   10 Leaves broad, not linear, nor strongly congested; [collectively more widespread]
                     11 Flowers solitary, terminal; [subfamily Ixoroideae; tribe Gardenieae]
image of plant
Show caption*© Alan M. Cressler
image of plant
Show caption*© Alan M. Cressler
                     11 Flowers in cymose or thyrsoid inflorescences.
image of plant
Show caption*© Scott Ward
image of plant
Show caption*© Alan M. Cressler
                       12 Inflorescence cymose; some calyx lobes expanded into pink or reddish “flags”; leaves deciduous; domatia not present; [of s. SC southward]; [subfamily Ixoroideae; tribe Condamineeae]
image of plant
Show caption*© Alan M. Cressler
                       12 Inflorescences thyrsoid; calyx lobes inconspicuous; leaves evergreen; domatia present in secondary vein axils; [of ne. FL southward]
image of plant
Show caption*© Sequoia Janirella Wrens, some rights reserved (CC BY-NC), uploaded by Sequoia Janirella Wrens
image of plant
Show caption*© Keith Bradley
                          13 Lateral veins 3-6 on either side of the midvein; fruit white; petals yellowish, > 6 mm long; [subfamily Cinchonoideae; tribe Chiococceae]
image of plant
Show caption*© Alan M. Cressler
                          13 Lateral veins 8-14 on either side of the midvein; fruit red; petals white, <5 mm long; [subfamily Rubioideae; tribe Psychotrieae]
1 Herbs (or creeping subshrubs in Mitchella).
                            14 Leaves whorled; [subfamily Rubioideae; tribe Rubieae]
                              15 Flowers paired, the ovaries connate and developing into a single fleshy red fruit; leaves roundish; creeping subshrub; [subfamily Rubioideae; tribe Mitchelleae]
                              15 Flowers single or in inflorescences with multiple flowers, the fruits either dry or fleshy and yellowish or black; leaves various; herb; [subfamily Rubioideae; tribe Spermacoceae].
                                       19 Flowers in axillary or terminal clusters, or single in axils, not involucrate; flowers 4-lobed; styles 2.
                                         20 Flowers usually solitary in leaf axils; fruit separating into 2 parts.
                                         20 Flowers in terminal and axillary clusters; fruits not separating into 2 parts.
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