Marah (MAIR-uh) oreganus, Coast Manroot, is a type of wild cucumber. The name manroot refers to the large, vaguely human-shaped, woody or fleshy underground root. Some large tubers can weigh up to 100 pounds. This root also helps Marah survive extreme droughts. Marah is deciduous and in the fall the foliage dies back. After the first winter rains and as early in the “spring” as December Marah sends up rapidly growing shoots from this underground tuber.
Marah grows at low elevations west of the Cascades, from British Columbia to California. It can grow to 20 feet or more in length and is often seen trailing over the ground or clambering up into trees or shrubs, clinging with its ample spiraling tendrils. Leaves are maple-like, 6-8 in. across, heart-shaped at its base, divided into 5-7 pointed lobes. Flowers are white, deeply cup-shaped with 5 lobes, at stalk top. Fruit widely oval, tapering to point at the tip, streaked dark green, covered with prickles. Fruits look like cucumbers but are very bitter and poisonous, as much of the plant, if ingested. The fruits contain 4-16 brownish seeds and were used as beads by the local indigenous people. Although, Marah is poisonous the locals used it to treat a variety of ailments.Wild cucumbers are monoecious (individual flowers are either male or female) but both sexes are found on the same plant. The single flower is female (with an ovary) and the flowers grouped on a long stem are male (with pollen). Female flowers are found at the base of the stem bearing the male flowers. Also, they are self-fertile (pollen from the male flowers can fertilize the female flowers on the same plant).
Marah is in the Cucurbitaceae plant family. Examples of plants in this family are cucumbers, watermelons, squashes, pumpkins, and cantaloupes. This is a medium-sized plant family, primarily found in the warmer regions of the world. It is a major family for economically important species, particularly those with edible fruits. The family contains some of the earliest cultivated plants in both the Old and New Worlds. Best of luck and happy gardening.
Wikipedia offers a quick synopsis about Marah oreganus.