''Marah fabacea'' (sometimes spelled ''Marah fabaceus''), the California manroot or bigroot, is the most common of the manroot species native to California. Its range throughout the state subsumes nearly the entire ranges of all the other California native manroots species and intergrades. Hybrids between California manroot and other species of '' Marah'' are common.

Foliage

Like other manroots, ''Marah fabacea'' has stout, hairy stems with tendrils. Vines appear in late winter in response to increased rainfall, and can climb or scramble to a length of 6 meters. Its leaves typically have five lobes with individual plants showing wide variation in leaf size and lobe length. Vines emerge from a large, hard tuberous root which can reach several meters in length and weigh in excess of 100 kilograms. Newly exposed tubers can be seen along roadcuts or eroded slopes and have a scaley, tan-colored surface. Injured or decaying tubers take on a golden or orange color.

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 Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is conne ...

, 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; pollen from the male flowers can fertilize the female flowers on the same plant. Pollination is by insects.

Fruit

The fruit is spherical, 4 to 5 centimeters in diameter, and covered in prickles of variable density, up to 1 centimeter 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 spring and ripen by early summer. The fruit can induce vomiting and diarrhea.

Seeds and germination

Seeds of the California manroot are large, hard, and very smooth. Fruit usually hold 4 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.

Ecology

The California manroot grows most vigorously by streams or in washes but is also successful in dry

chaparral Chaparral ( ) is a shrubland plant community and geographical feature found primarily in the U.S. state of California, in southern Oregon, and in the northern portion of the Baja California Peninsula in Mexico. It is shaped by a Mediterranean c ...

, at elevations up to 1600 metres. It ranges through most of California except the far northwest and the Mojave Desert. 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. In mild areas where year-round moisture is available, vines can be perennial. In the Mediterranean climate areas of California, manroot emerges soon after winter rains begin, grows until late spring, and dies back completely in the heat and dryness of summer.

Taxonomy

Two varieties have previously been recognized: ''Marah fabaceus'' var. ''agrestis'' (found in the San Francisco Bay Area and

Contra Costa County ) of the San Francisco Bay , subdivision_type = Country , subdivision_name = United States , subdivision_type1 = State , subdivision_name1 = California , subdivision_type2 ...

), and ''Marah fabaceus'' var. ''fabaceus'' (found elsewhere in California). An example occurrence of ''M. f. agrestis'' is on Ring Mountain in

Marin County, California Marin County is a County (United States), county located in the northwestern part of the San Francisco Bay Area of the U.S. state of California. As of the 2020 United States Census, 2020 census, the population was 262,231. Its county seat and ...

Uses

The tubers of ''Marah fabacea'' were crushed and thrown into surface waters by the

Kumeyaay The Kumeyaay, also known as Tipai-Ipai or by their historical Spanish name Diegueño, is a tribe of Indigenous peoples of the Americas who live at the northern border of Baja California in Mexico and the southern border of California in the Unit ...

to immobilize fish. The tubers contain megharrhin, a

saponin Saponins (Latin "sapon", soap + "-in", one of), also selectively referred to as triterpene glycosides, are bitter-tasting usually toxic plant-derived organic chemicals that have a foamy quality when agitated in water. They are widely distributed ...

-like

glucoside A glucoside is a glycoside that is derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes. The name was o ...

. Saponins lower the

surface tension Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension is what allows objects with a higher density than water such as razor blades and insects (e.g. water striders) to f ...

of water allowing the formation of bubbles. It is likely that the substance enters the fish's circulation through the gill arches where only a single-cell

epithelium Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellul ...

separates the water from the animal’s red blood cells. The affected fish float to the surface.Christina A. Bjenning. 2005 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. Due to its saponin content, the large tuber of the manroot can be processed for a soap-like extract. The liquid inside the fruit is an eye irritant, and the spines on the fruit are irritating to the skin.

References

* * C. Michael Hogan. 2008. ''Ring Mountain'', The Megalithic Portal, ed. Andy Burnha

Jepson Manual - ''Marah fabaceus''

External links

''Marah fabaceus'' - U.C. Photo gallery
{{Taxonbar, from1=Q17430123, from2=Q3845274 Cucurbitoideae Flora of California Flora of Nevada Flora without expected TNC conservation status