Monday, January 30, 2012

Wild cucumber, or manroot, of North America



Wild cucumbers of the Marah genus (gourd family, Cucurbitaceae) are found on the west coast of North America. The common name “manroot” refers to the large underground tubers that can weigh up to 100 pounds [1]. From these tubers, wild cucumbers sprawl or climb as vines with the help of tendrils that attach the growing plants to shrubs and trees. Most striking (and pricking) are the eye-catching spiny balls, one to two inches in diameter. Sometimes they are dangling from a vine—as in the pictures herein, showing a plant along the Ojai Pratt Trail through chaparral-like habitat south of Santa Barbara in California. The unripe, green fruits typically ripen into non-edible, yellow to brown fruits. The large leaves are palmetedly lobed, with five to seven lobes.

In a recent Bay Nature article entitled “Cool as a Cumber,” Jake Sigg features the two Marah species (M. fabaceus and M. oreganus) that grow in shrublands around and beyond San Francisco Bay [2]. He describes their emergence from summer dormancy with the advent of autumn rains. The best time to admire the spiny fruits is winter. With the beginning of the dry season in spring, the herbage turns yellow-brown and dies back to the tuberous root.

Like with all species in the gourd family, the flowers of the Marah are unisexual [3]: individual flowers are either male or female. But both sexes can be found on the same plant (monoecious plants), on which male flowers fertilize the female ones.

References and more to explore
[1] wiseGEEK: What Are Wild Cucumbers? [http://www.wisegeek.com/what-are-wild-cucumbers.htm].
[2] Jake Sigg: Cool as a Cucumber. Bay Nature January-March 2012, page 10. Also see Sigg's Wild Cucumber (Marah) article at collective roots and his San Francisco Natural Areas contribution.
[3]  Gourd Family (Cucurbitaceae) - Biology of Gourds: science.jrank.org/pages/3083/Gourd-Family-Cucurbitaceae-Biology-gourds.html.


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