common hop

not listed

N4? - Secure

SNR - Unranked

not listed

FACU - Facultative upland

FACU - Facultative upland

FACU - Facultative upland

Common hop (var. pubescens) is a perennial vine that rises from a stout rhizome. It dies back to the ground each year.

The stem is stout, non-woody, light green, and branched. It is solid at maturity and usually finely ridged or angled. It is rough and prickly to the touch, and is sparsely to moderately covered with stiff, 2-branched hairs on the ridges. Each hair has two rigid branches that spread in opposite directions. These hairs facilitate climbing by anchoring the vine to adjacent plants or structures. The stem is hairiest at the nodes, and is hairless or minutely hairy between the branched hairs. It climbs by turning clockwise at the tip (twining). Charles Darwin observed that it made a complete revolution every 128 minutes during daytime in hot weather.

Leaves are opposite, broadly egg-shaped in outline, and heart-shaped at the base. They are on ⅜″ to 3″ long leaf stalks (petioles). The petioles are usually shorter than the leaf blades. They are sometimes twining and, like the stem, are covered with stiff, 2-branched hairs. At the base of each leaf is a pair of lance-shaped, leaf-like appendages (stipules). The stipules are sometimes fused, appearing as a single stipule. Leaf blades are 1¼″ to 6″ long, and ¾″ to 5″ wide. They are mostly palmately divided into usually 3, rarely 5, lobes. The lobes taper to a point at the tip and are somewhat narrowed at the base. Leaves that are 4″ long or longer usually have fewer than 5 lobes. Smaller leaves are sometimes unlobed. Leaves 2″ long or shorter often have no more than 3 easily visible secondary veins branching off of the midrib, not counting branches near the base. The upper surface of the leaf blade is rough to the touch and is sparsely covered with stiff, prickly hairs. The lower surface is not rough to the touch. It is sparsely to moderately covered with short, fine, soft, white hairs along the veins and hairless but with yellow glands between the veins. The margins are toothed with sharp, forward pointing teeth.

Male and female flowers are borne on separate plants. The male inflorescence is loose, branched cluster (panicle) of 20 to 100 or more flowers at the end of the stem and drooping from leaf axils. The panicles are 1¼″ to 6″ long, and ¾″ to 1¼″ wide. The female inflorescence is a pair of dense, cone-shaped, ⅜″ to ¾″ long spikes (aments) drooping from leaf axils. The ament consists of overlapping, dull green bracts.

Male flowers are star shaped, 1 ⁄32″ to ⅛″ long, and about ¼″ wide. There are 5 yellowish- or whitish-green sepals, no petals, and 5 stamens with glandular anthers. Female flowers consist of an ovary with a long, slender stigma. They are paired between overlapping bracts of the ament.

The ament elongates when in fruit, becoming ⅜″ to 2″ long. The bracts are ⅜″ to ¾″ long, egg-shaped, and hairless along the margins. The fruit is a yellowish, broadly egg-shaped to nearly spherical achene enclosed in a persistent, enlarged calyx and covered by a papery bract. It is covered with yellowish to orangish stalked glands that secrete a bitter substance, lupulin, used to flavor beers.

Climbing: 3″ to 20″ long

Yellowish or whitish

Common hop (Humulus lupulus var. lupuloides) lower leaf surface is not conspicuously hairy. It is sparsely to moderately, not densely, hairy along the veins and is hairless between the veins.

Japanese hop (Humulus japonicus) is an annual. The petiole is as long or longer than the leaf blade. The leaf blade has 5 to 9 lobes. The leaf underside is rough to the touch with stiff, prickly hairs along the veins. The margins on the ament bracts are densely hairy. The bracts, anthers, and achenes are not glandular.

Moist. Thickets, woodland borders, riverbanks, wooded bluff slopes, fencerows, railroads, disturbed areas. Partial sun.

July to August

Sources

7, 28, 29, 30.

Native