1 Leaves connate at the base, opposite; flowers solitary in the axils of leaves; flowers 3-4-merous; [subfamily Crassuloideae]

1 Leaves distinct, whorled or alternate; flowers in terminal cymose inflorescences; flowers 4-5 (-8)-merous.

  2 Petals connate as a tube; leaves serrate, bearing plantlets in the serrations; [subfamily Kalanchoideae]

  2 Petals distinct or at most basally connate; leaves entire, crenate, or serrate, but not bearing plantlets along the margin; [subfamily Sempervivoideae].

    3 Plants with spheroidal basal rosettes consisting of dozens or more spirally arranged leaves; flowers 8-16-merous

    3 Plants with or without basal rosettes (if rosettes present, these not as above); flowers 4-6-merous

      4 Flowers 4-5-merous.

        5 Perennials without rosettes, the stems 0.5-10 dm tall (dying back in winter to the rootstock); leaves large, relatively thin in texture, usually 5-25 times as wide as thick, often crenate; flowers pink, purple, white, or greenish.

          6 Flowers 5-merous, bisexual; flowering stems 2-10 dm tall, from an underground, tuberous base; average leaves 3-11 cm long, 1-5 cm wide; ovaries attenuate at the base; [tribe Telephieae]

          6 Flowers 4 -(5)-merous, usually unisexual and then the plants dioecious; flowering stems 0.5-4 dm tall, from axils of brown scale-leaves clothing a stout rootstock at least in part exposed aboveground; average leaves 1-5 cm long, 0.4-1.5 cm wide; ovaries not attenuate at the base; [tribe Umbiliceae]

        5 Perennials or annuals with or without rosettes, the stems < 2 dm tall (the perennials with stems persistent through the winter); leaves smaller, flat or terete, relatively thicker, entire; flowers white or yellow; [tribe Sedeae].

             7 Leaves flat; leaf margins toothed or crenate.

               8 Leaves alternate; petals yellow

               8 Leaves opposite; petals white to pink

             7 Leaves flat, subterete, or terete; leaf margins entire.

                 9 Carpels united basally (to about 1/3 their length); petals cucullate, initially partly enclosing 4 of the 8 stamens; follicles dehiscing by a tear-shaped valve on the lower surface; stem and leaves normally red; [of granitic flatrocks of the Piedmont of GA, NC, SC, and VA, and sandstone glades in TN, nw. GA, and AL]

                 9 Carpels free; petals flat, never enclosing any of the 8 anthers; follicle dehiscing by a longitudinal slit along the adaxial (upper) suture; stem and leaves normally green, sometimes somewhat pink or reddish; [collectively of various habitats, including similar habitats as Diamorpha]

1 Leaves primarily whorled in 3's or 4's (to 5’s).

  2 Largest leaves distinctly spatulate, much wider than thick, 8-20 mm wide; flowers and fruits 4-merous; petals white; [native, of moist forest and rock outcrops]; [section Ternata]

  2 Largest leaves linear-lanceolate, oblanceolate, or elliptic, almost as thick as wide, < 7 mm wide; flowers and fruits 5-merous; petals yellow; [exotic].

    3 Leaves 4 (-5) per whorl; flowering shoots erect

    3 Leaves 3 (-4) per whorl; flowering shoots pendulous, creeping, or ascending.

      4 Flowering shoots pendulous or ascending; leaves linear-lanceolate

      4 Flowering shoots creeping or ascending; leaves oblanceolate to elliptic

1 Leaves primarily alternate.

        5 Flowers and fruits 5-merous.

          6 Leaves 2-5 mm long; petals yellow.

             7 Plant perennial, mat-forming by trailing stems; leaves yellow-green; petals 5-9 mm long, with acute to acuminate apices; [exotic, usually in urban or suburban areas]

             7 Plant annual, stems solitary; leaves pal- or bluish green; petals 2-4 mm long, with mucronate apices; [native, of shallow soils over rock]

          6 Leaves 6-15 mm long; petals yellow or white.

               8 Petals white; flowers 5-merous

        5 Flowers and fruits 4-merous.

                 9 Leaves of flower-bearing stems linear, sagittate-spurred at the base (the spurs clasping the stem); petals pink to white; annual; [section Ternata]

                 9 Leaves of flower-bearing stems narrowly elliptic, oblanceolate, spatulate, cuneate or short-spurred at the base (not clasping); petals white; perennial or annual.

                   10 Plants annual; sepals 0.4-1 mm long; petals 1.4-4.2 mm long; [restricted to shallow soils of granitic flatrocks of the Piedmont, from s. NC south to wc. GA]; [section Tetrorum]

                   10 Plants perennial; sepals 2-9 mm long; petals 4-9 mm long; [of outcrops of various rocks, not as above]; [section Ternata].

                     11 Leaves of flowering stems with width/thickness ratio of > 2.0; seeds averaging 0.8 mm long; leaves pale green or bluish green, sometimes with a glaucous coating; primary rosettes usually 1.0-2.7 cm in diameter; [MD south through VA and WV to sc. and sw. NC]

                     11 Leaves of flowering stems with width/thickness ratio of < 1.7; seeds averaging 0.7 mm long; leaves green or gray-green, but not glaucous; primary rosettes usually ca. 1 cm in diameter; [se. TN south into AL and GA]