1 Flowers 3-merous, with 3 sepals and 3 petals; carpels 3; leaves even-pinnate or odd-pinnate, with (4-) 6-8 (-10) leaflets; [of s. FL]; [section Tobinia]

1 Flowers 4-6-merous, either with 4-5 sepals + 4-5 petals, or with 4-8 undifferentiated tepals; carpels 1-4 (-5); leaves odd-pinnate, with (3-) 5-13 leaflets; [collectively widespread in our area].

  2 Petioles and rachises winged; leaflets 0.5-7 (-8) cm long.

    3 Leaflets 1-3 (-8) cm long, 0.3-0.7 (-1.8) cm wide, rounded and usually retuse at the apex; [of peninsular FL and se. and s. TX southwards]; [section Pterota]

    3 Leaflets 2.5-5 (-7) cm long, 1.5-4 cm wide, acuminate to obtuse at the apex; [planted horticulturally, and sometimes persistent or weakly spreading]; [section Sinensis]

  2 Petioles and rachises not winged; leaflets 4-10 cm long.

      4 Twigs, leaves, and inflorescences stellate-canescent; plants without prickles; [of s. FL]; [section Macqueria; Zanthoxylum rhoifolium group]

      4 Twigs, leaves, and inflorescences hirtellous, puberulent, or glabrous, the hairs simple; twigs and leaves generally bearing prickles; [collectively widespread in our area].

        5 Leaves thin in texture, pubescent; leaflets 5-9 per leaf; flowers and fruits borne in small axillary clusters or fascicles; carpels (1) 2-4 (-5); [mainly in inland physiographic provinces, but also rare and scattered in the Coastal Plain]; [section Zanthoxylum]

        5 Leaves coriaceous in texture, glabrous (or glabrate) and waxy, the lateral leaflets oblique at the base (asymmetrical across the midvein); leaflets (5-) 11-15 (-19) per leaf; flowers and fruits borne in large terminal and subterminal panicles or corymbs; carpels 1-2; [mainly Coastal Plain, but extending northwards into inland provinces in n. AL, AR, OK, and TX]; [section Macqueria; Zanthoxylum clava-herculis group].

          6 Leaflets (1.5-) 2-4 (-5) cm long, 1-2 (-2.3 cm wide; inflorescences 2.5-7 cm long, with 1-2 orders of branching;