California manroot

Marah fabacea, the California manroot or bigroot, is a coarse herbaceous perennial vine of the Cucurbitaceae endemic to California and adjacent Baja California, growing from a massive woody tuber that can exceed 50 kg and 1 m in length. From this tuber arises in winter and spring a sprawling or climbing annual stem 2–6 m long, branched and equipped with bifid tendrils. Leaves are alternate, palmately 5–7 lobed, 5–15 cm wide, scabrous-pubescent, with toothed lobes. Plants are monoecious: staminate flowers are arranged in long open racemes of 10–30 white to cream, broadly campanulate corollas 8–12 mm across with 5–6 spreading lobes; pistillate flowers are solitary in the same leaf axil, with an inferior ovary densely covered in soft prickles. Fruits are subglobose to ellipsoid spiny capsules 4–8 cm in diameter that dry to a fibrous husk and split irregularly to release 4–8 large, smooth, oily seeds. The entire plant contains bitter triterpene cucurbitacins and is toxic.