1 Leaves simple; leaf margins entire; shrubs, trees, and herbs; [subfamily Phyllanthoideae].

..2 Herbs.

....3 Plant with “normal” arrangement of branches and leaves (leaves uniformly distributed on the stem and branches, alternate and either distichous or spirally arranged, the ultimate branches not deciduous, flowers produced on ultimate and penultimate orders of branches).

......4 Leaves arranged spirally; staminate sepals 0.7-2.5 mm long; stipules not auriculate

......4 Leaves arranged distichously; staminate sepals 0.5-0.7 mm long; stipules typically auriculate

....3 Plant with “phyllanthoid” arrangement of branches, leaves, and flowers (leaves lacking on the main stem, the penultimate order of branches with scales arranged spirally, the ultimate (final) order of branches deciduous, bearing normal leaves alternately and distichously, flowers produced only on the ultimate, deciduous branches), the ultimate branches and their distichous small leaves resembling the rachis and leaflets of a once-pinnate compound leaf.

........5 Fruiting pedicels 0.5 mm long; seeds with 12-15 transverse ridges and sometimes 1-3 pits; male flowers borne toward the tip of the branchlets, female flowers toward the base

........5 Fruiting pedicels > 0.5 mm long; seeds either longitudinally ribbed or striate, or verrucose; female flowers borne toward the tip of the branchlets, male flowers toward the base

..2 Shrubs or trees.

..........6 Ultimate branchlets flattened into cladodes; leaves on ultimate branchlets scale-like, caducous; flowers borne in axils of scales, in notches of the cladodes

..........6 Ultimate branchlets terete, "normal"; leaves on ultimate branchlets leaf-like, flattened , with a blade; flowers borne in axils of leaves.

............ 7 Plant with “normal” arrangement of branches and leaves (leaves uniformly distributed on the stem and branches, alternate and either distichous or spirally arranged, the ultimate branches not deciduous, flowers produced on ultimate and penultimate orders of branches); staminate flowers lacking pistillodes.

............ ..8 Leaves deciduous; fruits berries, 3-5 mm in diameter; petals absent; nectary in staminate flowers of of 5 glands

............ ..8 Leaves evergreen; fruits capsules, 3.6-7 (-9) mm in diameter; petals present; nectary in staminate flowers an annular disc.

............ ....9 Staminate flowers 6-25, sessile to subsessile in a glomerule; pistillate petals 1-2 mm long; shrub or tree to 4 (-8) m tall; [FL keys]

............ ....9 Staminate flowers 1-2 (-4), pedicellate in a fascicle; shrub to 1 m tall; pistillate petals 0.4-0.8 mm long; [inland provinces, AL, TN, MO, AR, OK, TX]

............ 7 Plant with “phyllanthoid” arrangement of branches, leaves, and flowers (leaves lacking on the main stem, the penultimate order of branches with scales arranged spirally, the ultimate (final) order of branches deciduous, bearing normal leaves alternately and distichously, flowers produced either only on the ultimate branches [Breynia disticha, Glochidion puber], or on short shoots on old wood [Cicca acida]), the ultimate branches and their distichous small leaves resembling the rachis and leaflets of a once-pinnate compound leaf; staminate flowers with pistillodes

............ ......10 Fruits greenish white to yellow-orange drupes, (12-) 15-20 (-25) mm in diameter; inflorescences borne on short shoots on old growth

............ ......10 Fruits capsules, 4-15 mm in diameter; inflorescences borne in axils of leaves on the ultimate branches.

............ ........11 Leaf blades ca. 1.5× as long as wide, broadly rounded at the apex; pistils 3-carpellate, each of the 3 styles 2-branched

............ ........11 Leaf blades3× as long as wide, acute to acuminate at the apex; pistils 5-10-carpellate, each of the 5-10 styles unbranched