Besides the species included here, many others are grown and may spread from cultivation; the plants propagate easily from detached fragments, often distributed by water or other means. Such species will be best identified through works on cultivated plants. Sedum sediforme (Jacq.) Pau was collected in 1974 in Ann Arbor (Washtenaw Co.) as “spreading in a garden.” It does not appear to have become established. It is larger than our other species, with yellowish-green flowers and linear, terete leaves 1–1.5 cm long.
1. Leaves definitely flat (though succulent), the largest over 3 mm wide, some or all in whorls of 3.
2. Flowers yellow, 5-merous; larger leaves 3–4 mm wide, narrowly elliptic to lanceolate, not crowded in rosettes (internodes elongate).
2. Flowers white, 4-merous; larger leaves 7–14 mm wide, obovate, on the vegetative shoots crowded in terminal rosettes.
1. Leaves terete to elliptic in cross-section, less than 3 mm wide, alternate.
3. Flowers white to pink; leaves of flowering stem not overlapping, the internodes conspicuous.
4. Stem (at least distally) and inflorescence glabrous; petals 5, acute.
4. Stem and branches of the inflorescence at least sparsely and minutely glandular-pubescent; petals usually 6, acuminate.
3. Flowers bright yellow; leaves of flowering stems ± densely overlapping, ordinarily obscuring the stem.
5. Leaves ± ovoid, broadest toward the base, not clearly ranked; petals ca. 5–7 mm long.
5. Leaves linear-cylindric (like minute sausages), generally 6-ranked on vegetative shoots; petals ca. 4–5 mm long.