Marah macrocarpa (sometimes spelled Marah macrocarpus), known as chilicothe, wild cucumber, manroot or bigroot is a species of plant in the genus Marah.[1]
Marah macrocarpa has the most pubescent shoots, stems, and leaves of all the Marah species native to California - this being consistent with its range having the most xeric climate. Vines appear in late winter in response to increased rainfall, and can climb or scramble to a length of 6m (20feet). The subspecies M. m. major of the Channel Islands (California) is about twice as large in all of its parts.[2] For example,the mainland leaves are 5 to 10 centimeters wide while the insular leaves are 15 to 25 centimeters in width. And the seeds on the mainland are 15 to 20 millimeters long while the insular seeds are 28 to 33 millimeters in length.[3]
Vines emerge from a large, hard tuberous root which can reach several meters in length and weigh in excess of 100kg (200lb). Weights of up to 500 pounds (227 kilograms) have been reported.[4] Vines develop leaves and, particularly, flowers and fruit very quickly, often with the first nodes of the quick-growing vines containing male and female flower heads. Its leaves typically have five lobes with individual plants showing wide variation in leaf size and lobe length.
Three varieties were formerly recognised:
The plant is native to Southern California and Baja California. Its range extends from the Transverse Ranges and Channel Islands through the Peninsular Ranges.[1]
It grows by streams, in washes, and on slopes in chaparral and oak woodlands, at elevations up to . It will tolerate a variety of soil types and acidities, but it requires seasonally moist soil. Vines can grow in full-sun to partially shaded conditions. It emerges soon after winter rains begin, grows until late spring, and dies back completely in the heat and dryness of summer.
All parts of the plant have a bitter taste (this is the meaning of the genus name Marah, which comes from Hebrew). Despite this, the leaves have been used as a vegetable. The large tuber of the manroot can be processed for a soap-like extract.