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Idaho Mountain Wildflowers

Stonecrop Family: Crassulaceae

The stonecrop family consists of 33 genera and approximately 1,500 species. Crassulaceae are found on all continents with the exception of Australia and Antarctica. Most of its members are thick-leaved succulents. The family takes its scientific name from the word crassula, an older generic term for the sedums and now a name of another genus in the family. The word probably was derived from the Latin crassus, meaning “thick,” for the succulent leaves found throughout the family. The only economic importance of the Crassulaceae is that many—for example, the jade plant (Crassula ovata) from East Africa, the flowering red kalanchoe (Kalanchoe blossfeldiana) from Madagascar, and hen and chickens plants (Jovibarba spp.)–are popular ornamentals. Sedum is the largest genus in the family.

	Wormleaf stonecrop, Sedum stenopetalum Pursh (left), and Lanceleaf stonecrop, Sedum lanceolatum Torr. (right & below). The two stonecrops shown here are related plants with similar yellow flowers and the thick leaves typical of sedums, although they each have distinguishing characteristics. The leaves of the wormleaf stonecrop stand away from the stem, whereas those of the lanceleaf stonecrop remain appressed. Similarly, when the follicles (dried seed capsules) are ripe, the wormleaf stonecrop’s follicles protrude horizontally, whereas those of the lanceleaf plant are borne nearly upright. Finally, the wormleaf sedum retain its leaves when the plant is in full flower, whereas those of the lanceleaf sedum are shed, as seen below. Thanks to water stored in the leaves, stonecrops thrive when rooted in the organic debris that collects in rocky cracks and depressions, without need of soil water—a phenomenon that explains the common name, “stonecrop.” Both plants grow at all elevations, almost always on rocks, or on rocky soil; we have seen lanceleaf sedum growing on alpine tundra. Meriwether Lewis collected both plants, on the same day (July 1, 1806) while camped at Traveler’s Rest near today’s Missoula, Montana.

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