Humulus japonicus
HEMP FAMILY (Cannabaceae)

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This invasive annual was introduced from East Asia. This herbaceous vine, up to 10 feet long, has very rough and clinging stems and leaves with pickles (D). The leaves are up to 8 inches long with 5-9 pointed lobes. This plant entangles and covers other nearby vegetation. Male and female flowers are on separate plants (dioecious). The male (staminate) flowers are white, later turning reddish (C), forming a loose, erect cluster (A). A single female (pistillate) flower is greenish (B); it develops into hops (E). Identified by the pointed leaves with 5-9 lobes and spines on lower leaf surfaces. The similar Common Hops (Humulus lupulus), also present in Fontenelle Forest, has leaves with 3-5 lobes which are not as rough to the touch.

On floodplains near lakes and streams, flowering from July through September. This vine is common along Redbud Trail in Fontenelle Forest, and is thriving where the floodplain was flooded in 2011.

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