1 Leaves coriaceous, evergreen.

  2 Leaves with a well-developed apical spine (and usually also marginal spines) 2-6 mm long.

    3 Flowers in 1-few-flowered axillary cymes, on growth of the same year; upper leaf surfaces somewhat shiny to matte; marginal leaf spines (when present) in the plane of the leaf or mostly declined < 30 degrees from that plane; [native trees of a wide variety of habitats]; [section Cassinoides]

      4 Leaves somewhat yellowish green above, 1.5-5.0 cm long, 1.0-2.5 cm wide, strongly revolute; fruits orange to red; [of dry sandy habitats of FL]

      4 Leaves dark green above, 3-12 cm long, 2.0-5.5 cm wide, flat to slightly revolute; fruits red (rarely yellow); [of moist to fairly dry habitats, widespread in our area]

    3 Flowers in axillary clusters, on growth of the previous year; upper leaf surfaces very shiny; marginal leaf spines (when present) often strongly oriented below or above the plane of the leaf; [exotic shrubs or small trees usually in suburban or urban areas]; [section Ilex]

        5 Lateral leaf margin spines > 5 per leaf side (rarely 0, in some cultivars)

        5 Lateral leaf margin spines usually 0, 2, or 4 per leaf side

  2 Leaves with margins either entire, crenate, serrate, or with marginal spinose prickles < 2 mm long (the apex sometimes mucronate, but not stiff and spinose).

          6 Leaves crenate from base to apex, 0.5-4.5 cm long; calyx and corolla 4-lobed.

             7 Fruits red or yellow; leaf undersurface lacking punctate glands; leaf apex notched (retuse), with a very small mucro in the notch (best seen at 10× or greater); [native shrub of the Coastal Plain, sometimes planted and naturalized elsewhere]; [section Repandae]

          6 Leaves entire, crenate (if so, only beyond the midpoint), serrate, or with marginal spinose prickles, 2-10 cm long; calyx and corolla 4-lobed or 5-9-lobed.

               8 Fruits black; calyx and corolla 5-9-lobed; leaves crenate near the tip or with a few marginal spinose prickles, or entire, with dark punctate dots beneath; [section Glabra].

                 9 Leaves 1.5-3× as long as wide, generally about 2-3 cm wide, broadly elliptic and widest near the midpoint of the blade; leaf margins either entire or with a few, irregularly spaced, marginal spinose prickles that diverge from the margin

                 9 Leaves 3-4× as long as wide, generally about 1 cm wide (almost never > 2 cm wide), obovate and widest beyond the midpoint of the blade; leaf margins crenate in the apical 1/2 to 1/3 (almost never entire)

               8 Fruits red, yellow, or black; calyx and corolla 4-lobed; leaves entire (or with a few spinose serrations), lacking dark punctate dots beneath.

                   10 Fruits black or purple when ripe; peduncle absent or very short (< 3 mm long), the flowers (later fruits) thus clustered in the leaf axils; [of s. FL only]; [section undetermined]

                   10 Fruits red or yellow when ripe; peduncle elongate; [more widespread in our area]; [section Cassinoides].

                     11 Leaves oblanceolate, oblong, or elliptic, 3-12 cm long, (8-) 15-40 mm wide, 2-4× as long as wide; petioles (3-) 5-15 mm long; leaf apex acute, obtuse, or rounded; branchlets strongly ascending, most of them forming an angle of < 45 degrees to the branch

                     11 Leaves lanceolate to narrowly oblong, 2-4 cm long, 3-8 mm wide, 3-7× as long as wide; petioles 1-3 (-5) mm long; leaf apex acute to acuminate; branchlets ascending to spreading, most of them forming angles greater than 45 degrees to the branch, and often at right angles

1 Leaves membranous, deciduous.

                       12 Leaves entire, or nearly so; [of moist to wet sites, from WV northward]; ["clade IV"]

                       12 Leaves toothed; [collectively widespread in our area].

                          13 Leaves oblanceolate or obovate, broadest above the middle (to near the middle), 8-30 (-45) mm wide, narrowly cuneate basally, mostly 2-3× as long as wide; [section Prinoides].

                            14 Pedicels of fruits and pistillate flowers 2-6 mm long; pedicels of staminate flowers (2-) 4-8 (-16) mm long; leaves mostly gray green, often revolute, especially toward the base; pubescence of the lower leaf surface tomentose, primarily on or near the midrib; leaf margins rarely ciliate.

                              15 Leaves 2-4.8 cm long, 0.6-1.5 cm wide; fruits 4-5 mm in diameter; sepals usually ciliate; [apparently endemic to the Suwanee River drainage of sc. GA and e. Panhandle FL]

                              15 Leaves 4.5-8.5 (-10) cm long, 1.5-3 cm wide; fruits (4-) 5-8 (-9) mm in diameter; sepals not ciliate; [widespread in our area, in the Coastal Plain, Piedmont, and rarely Mountains of our area]

                            14 Pedicels of fruits and pistillate flowers (5.5-) 10-30 mm long; pedicels of staminate flowers (10-) 15-25 mm long; leaves rarely revolute; pubescence of the lower leaf surface strigose, distributed on the surface; leaf margins often ciliate.

                                16 Upper leaf surface with trichomes throughout; sepals ciliate; leaf blades entire to shallowly crenate

                                16 Upper leaf surface glabrous, or with trichomes confined to the veins or their vicinity; sepals eciliate; leaf blades crenate to distinctly serrate

                          13 Leaves elliptic or ovate, broadest near the middle, (10-) 20-55 mm wide, rounded to broadly cuneate basally, mostly 1-2.5× as long as wide.

                                  17 Tertiary veins on undersurface of leaf blades reticulate, defining areoles between the raised primary and secondary veins; fruit surface dull; fruiting pedicels 6-14 mm long (averaging about 10 mm); [of blackwater floodplains and clay-based Carolina bays of the Coastal Plain]; ["clade IV"]

                                  17 Tertiary veins on undersurface of leaf blades obscure, not defining obvious areoles between the raised primary and secondary veins; fruit surface shiny; fruiting pedicels either (8-) 10-30 mm long or 2-9 mm long (averaging either < 6 mm or > 15 mm long); [collectively of various habitats, widespread in our area].

                                    18 Fruiting pedicels (8-) 10-30 mm long; fruit (7-) 8-12 mm in diameter, bright cherry-red; petiole with a deeply U- to V-shaped channel on its upper side (made by the decurrent leaf edges), with dark ascending trichomes in the channel; bark of 2-3 year old twigs usually light tan; [of bogs, seepages, and very moist forests of the Mountains]; [section Prinoides]

                                    18 Fruiting pedicels 2-9 mm long; fruit 5-9 (-12) mm in diameter, duller red to orange; petiole with U-shaped channel on its upper side, with white appressed trichomes in the channel, or the petiole nearly terete; bark of 2-3 year old twigs usually brown, gray, or purplish; [collectively of various habitats, widespread in our area].

                                       19 Nutlets (5-) 6-8 per fruit, smooth on the (curved) back; staminate flower clusters on peduncles 2-6 mm long; pistillate flowers with entire corolla lobes; flowers mostly in axils of leaves on normal shoots; petiole nearly terete in cross-section (or very shallowly channeled on the upper surface); [section Prinos].

                                         20 Sepals glabrous (in flower or fruit), acute; leaves lighter green, slightly if at all rugose

                                         20 Sepals ciliate (in flower or fruit), obtuse; leaves darker green, often moderately rugose

                                       19 Nutlets 4-5 per fruit, with striate ridges on the (curved) back; staminate flower clusters sessile or very short-peduncled (0-2 mm long); pistillate flowers with ciliate corolla lobes; flowers mostly in axils of leaves on lateral short-shoots; petiole with U-shaped channel on its upper side, with white appressed trichomes in the channel; [section Prinoides].

                                           21 Leaves 2-9 (-10.5) cm long, elliptic to broadly ovate, often nearly round, the base usually rounded, the apex abruptly to gradually acuminate, the marginal teeth usually inconspicuous; petioles of mature leaves usually < 1 cm long; fruits 5-9 mm in diameter; plant a shrub to 6 m tall; [of the Coastal Plain, Piedmont, and Mountains]

                                           21 Leaves 6-16 cm long (the largest, at least, > 8 cm long), narrowly to broadly ovate, the base usually cuneate, the apex long acuminate to attenuate, the marginal teeth rather coarse; petioles of mature leaves usually > 1 cm long; fruits 9-12 mm in diameter; plant a shrub or small tree to 10 m tall; [of the Mountains and upper Piedmont]