Marah Macrocarpa

''Marah macrocarpa'' is a species of plant in the genus '' Marah'' commonly referred to as chilicothe, wild cucumber, manroot or bigroot. It is a perennial herb with a large tuber native to Southern California and northern Baja California. It grows in a diverse number of habitats in coastal and inland regions. A member of the gourd family, it produces a large, green, prickly fruit. Indigenous peoples traditionally used it for treating hair loss and pain relief. All parts of the plant are toxic, as it contains cucurbitacins and ribosome-inactivating proteins.

Description

''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 . The subspecies M. m. major of the Channel Islands (California) is about twice as large in all of its parts. 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.

Vines emerge from a large, hard tuberous root which can reach several meters in length and weigh in excess of . Weights of up to 500 pounds (227 kilograms) have been reported. 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.

;Flower
The flower can vary in color from yellowish green to cream to white. Flowers appear soon after the vine emerges. The flowers are monoecious, that is, individual flowers are either male or female, but both sexes can be found on the same plant. Male flowers appear in open clusters while females flowers, distinguished by a swollen base, usually appear individually. The plant is self-fertile, i.e. pollen from the male flowers can fertilise the female flowers on the same plant; pollination is by insects.

;Fruit

The fruit is longer than it is wide, 5–6 cm in diameter and 15–20 cm long, and covered in prickles of variable density, up to 1 cm long but without hooks. Unripe fruit are bright green, ripening to yellow. The fruit swells as it ripens until finally rupturing and releasing the large seeds. Fruit begin to form in late winter and ripen by early summer.

;Seeds and germination
Seeds of ''Marah macrocarpa'' are large, hard, and very smooth. Southern California manroot has larger, longer seeds than the other manroot species except for '' Marah horridus''. Fruits usually hold four or more seeds. Seeds sprout in the cool wetness of late winter. Seeds have an intriguing germination process. The initial shoot emerges from the seed and grows downward into the earth. This shoot then splits, one part beginning to swell and form the tuber, while the second part grows back to the surface and becomes the vine.

Taxonomy

Varieties for this species are sometimes recognized, depending on the authority. Kenneth Morgan Stocking circumscribed these varieties based on the sizes of the staminate flowers and seeds. The other dimensions of the plants follow these sizes in proportion.
*''Marah macrocarpa'' var. ''macrocarpa'' — The autonymic name. Staminate flowers in diameter and seeds long.
*''Marah macrocarpa'' var. ''major'' (Dunn) Stocking — A combination based off of ''Marah major'', a species described by Dunn. A larger variety endemic to the Channel Islands of Southern California. Staminate flowers in diameter and seeds long.
*''Marah macrocarpa'' var. ''micrantha'' (Dunn) Stocking — A combination based off of ''Marah micranthus'' (Dunn). Commonly known as the Cedros manroot. This very rare variety is endemic to Cedros Island in Baja California. Staminate flowers in diameter and seeds long.

Guadalupe manroot

''Marah guadalupensis'' (S. Watson) Greene, the Guadalupe manroot is a species endemic to Guadalupe Island in the Pacific Ocean. It is distinguished from other species of ''Marah'' by its large campanulate corollas, two-seeded fruit, and its longer, linear, pistillate sepals. ''M. guadalupensis'' is subject to different taxonomic treatments depending on the authority. Some authorities recognize it as a distinct species, while others recognize it as conspecific with ''M. macrocarpa''. Other authorities expand ''M. guadalupensis'' to include the Channel Islands manroot, ''M. macrocarpa'' var. ''major'' (or ''M. major''). Stocking noted similarities of ''M. guadalupensis'' in its flowers and fruit to '' Marah oreganus'' and suggested a close relationship.

Distribution and habitat

''Marah macrocarpa'' is native to Southern California in the United States and Baja California, Mexico. Its range extends from the Transverse Ranges and Channel Islands through the Peninsular Ranges, and the Sonoran Desert. ''M. macrocarpa'' is bounded to the north by the Santa Clara River, which also forms the southern boundary for '' Marah fabacea''. It occurs throughout Baja California and its adjacent Pacific islands, including Cedros Island.

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.

Uses

Ethnographic accounts report that the most common use of ''Marah macrocarpa'' was for treating hair loss and baldness on the head. It was reported that the Chumash, Kawaiisu, and Cahuilla peoples roasted the seeds and mashed them into an oily black salve that was applied to the head. Pharmacological research suggests that the Cucurbitacins found in ''Marah'' are structurally similar to the antiandrogen medication finasteride and may show similar biological activity, providing support to the traditional uses of the plants for treating hair loss.

The Kumeyaay, Luiseño, Kawaiisu, and Tongva peoples also used ''M. macrocarpa'' for the relief of pain and inflammation. The black salve from the roasted seeds was applied to areas of irritation or sores. The black salve was also used for body painting.

All parts of the plants are toxic due to the presence of cucurbitacins and ribosome-inactivating proteins, so it was not traditionally consumed. Other ''Marah'' species in different regions were historically consumed in difficult conditions to commit suicide or euthanasia.

References

External links

UC CalPhotos gallery: ''Marah macrocarpa''

{{Taxonbar, from1=Q17430121, from2=Q6754651
Cucurbitoideae
Flora of California
Flora of Baja California
Flora without expected TNC conservation status
Plants used in traditional Native American medicine