Lobed and lightly hairy M. horridus leaf.
Marah horridus is also called Sierra Manroot. As its name suggests, M. horridus grows from the central Sierra Nevada foothills south into the Transverse Ranges. Its range overlaps with M. watsonii in the north and M. macrocarpus in the south. It is often found growing beneath oak trees at elevations below 5,000 feet.


Rough-surfaced male flowers.

M. horridus stems are a slightly gray-green color and densely pubescent. The leaves differ from M. fabaceus by having more smaller hairs and deeper, rounded lobes. In addition, M. horridus leaves are less shiny that other species.

M. horridus flowers are generally white with flat petals and have a rough surface. Male M. horridus flowers are the most bell-shaped of the genus and hang from the bloomstem on short curved stems. Female flowers appear singly at the base of the male bloomstem and are less bell-shaped.


Female flower with unfertilized fruit.

The densly prickled fruit of M. horridus are the largest of the genus and hang from the vines on long stems. The smooth, hard seeds are also the largest of the genus and taper to a pointed end. Like all manroot, the fruit swells as it ripens before ejecting the large seeds.

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