Wild Hop (Humulus lupulus).
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The Wild Hop may not unfrequently be seen in the copse and hedgerow, especially in the South of England. It has a thick branching perennial rootstock—in the cultivated plant called a "set"—from which are produced several long, thin, but tough twining stems that turn with the sun, and tightly clasp the nearest small tree or shrub. It has no tendrils like the vine, but climbs like the convolvulus by simply twining with the sun as it grows. Its lobed and coarsely toothed leaves are very similar to those of the grape-vine, but very rough. The leaves are in pairs, and at the base of the leaf- stalk is a pair of long curved stipules. The Hop is what botanists term a diœcious plant, because staminate flowers only are produced by one individual, and pistillate only by another, making cross-fertilization imperative. It is not the insects, however, that effect this crossing in the Hop, but the wind. The flowers are all small; the staminate produced from the axils of the leaves in long drooping panicles. They have no petals, but there are five sepals and five anthers attached to their bases. Each pistillate flower has a membranous sepal, an ovary, and two long tapering purple stigmas. Two of these pistillate flowers are produced in the axil of a green, broad, concave bract or scale. A number of these twin-flowered bracts are united into a dense spike, and after fertilization this develops into a large cone-like head of yellow scales with resinous glands at their base, which yield a resinous substance called lupuline. The true fruit is a little nut, which is enclosed in the sepal under the bracts. It flowers in July and August. It is the only British species. Beside their extensive use in brewing, the flowers are frequently used to stuff pillows, their narcotic odour inducing sleep.
