Leaves orbicular (round) or cordate (heart-shaped). Leaves palmately lobed, diverging from a common base. Leaves ~5-10 cm long and wide, flat, with 5-7 lobes and indentations, with a petiole ~3-8 cm long. Light to medium green, usually a bit pubescent (hairy/downy) or a dull glabrous (smooth-surfaced). Two distinctive flower genders carried on one plant (monoecious). Male flowers (~0.8-1.3 cm across) are usually white, with small oval petals, carried on a raceme coming out of the leaf axils, with anywhere between 8 and 20 flowers, each on a short (~0.3-0.5 cm) pedicel, on a raceme. Female flowers, usually white and ~1.5-2 cm, are singular but are found emerging from the same leaf axils as the male flower racemes. Blooms January to April. Fruit is a cylindrical gourd ~8-12 cm long, densely covered with spines about 0.5-3 cm long. Annual plant grows as a sprawling vine, commonly spreading out 3-7 m. Puts out corkscrew tendrils at the leaf axils, with which the vine clings to objects and climbs onto them. Though the plant is a kind of cucumber, it is very bitter in taste throughout, and its generic name comes from a Hebrew word meaning "bitter."
Marah macrocarpus (Cucurbitaceae): manroot or Cucamonga manroot or bigroot or wild cucumber
The development of this key was partially funded through the Geoscience Diversity Enhancement Program (Award #0703798) and through a course of re-assigned time provided by the CSULB Scholarly and Creative Activities Committee. Thanks also to the students in sections of biogeography, introductory physical geography, GDEP, and LSAMP for "test-driving" various editions of this key.