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U.S. Forest Service

Plant of the Week

Dudleya cymosa range map. Dudleya cymosa range map. USDA PLANTS Database.

Dudleya cymosa. Canyon live-forever.

Dudleya cymosa. Canyon live-forever, Sierra National Forest, California. Photo © Charles Webber, California Academy of Sciences (1998).

Live-forever (Dudleya cymosa ssp. cymosa)

By Forest Jay Gauna

Live-forever is a member of the Stonecrop Family (Crassulaceae), which provides thousands of succulent plant enthusiasts with friendly, fleshy, spineless-leaved plants to grow. The family lent its name to Crassulacean Acid Metabolism (CAM), a process often used by succulent desert plants to conserve water for themselves. Plants use energy from the Sun to form sugars out of carbon dioxide in the process called photosynthesis. In order to obtain the carbon dioxide, plants have little pores in their leaves called stomata, which can be opened and closed; a certain amount of water vapour escapes as the plant is taking in CO2. In dry places, this can be a real problem for plants: the water will leave the plant very fast because the air outside of the leaf is so dry, and the plant will have less water at its disposal to replace the water lost. The plant could close its stomata, but then it would have no carbon dioxide with which to grow. The solution of many succulents is to close their stomata during the day and open them at night, when it is cooler and less water will escape. The plant then takes in CO2, converts it into a storable acid, and waits for daylight, when it will convert the acid back to CO2 and carry out photosynthesis while the stomata are closed. This allows succulents to retain their water with great efficiency.

Aside from its ethnobotanic use to plant physiology professors, the written ethnobotanic records of this nation are scant with references to this species, or even the genus: some live-forever leaves were eaten for food or prepared as medicine, but it was more than likely regarded as a curiosity than a plant of great utilitarian promise. The genus was named for a 19th century California botanist. The species is called cymosa because it has inflorescences in cymes.

D. cymosa ssp. cymosa grows in California and southwestern Oregon, from a few hundred to about 9,000 feet in elevation; it likes rocky areas, in cliffs and mountains. It does best in semi-arid places. The leaves are classic Crassulaceae leaves: greyish-green, thick and fleshy; this species’ leaves usually come to a tip or point. The plant remains a squat rosette of leaves until it flowers, at which time it sends up from the centre a bright red inflorescence stem, bearing flowers in cymes. The petals are vivid yellow on the inside, and yellowish to reddish on the outside; the flowers are exceptionally beautiful and bright. At first glance, the flowers (and indeed the entire plant) can appear made of plastic, because of their waxy sheen; the thick waxy cuticle is yet another means to help minimize water loss.

None of my sources indicate why it is named ‘live-forever,’ but a member of the family has grown in a pot at my family home for two decades, when it was given us as a gift. Given that many of these plants reproduce clonally, it is theoretically possible that some plants have been cloning themselves for decades, or perhaps even centuries.

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