H. Lupulus: stems twining to a considerable height over bushes and small trees; leaves opposite, stalked, broadly heart-shaped, deeply 3-5-lobed, sharply-toothed, rough but not stinging; flowers dioecious: the males in loose panicles in the upper axils, small, yellowish-green; the females in shortly stalked, axillary, ovoid or globular spikes or heads, conspicuous for their broad, closely-packed bracts, each with two sessile flowers in its axil, the perianth a concave scale enclosing the ovary; scales of the spike becoming enlarged after flowering, concealing the seed-like fruits. - Hedges, thickets, and open woods. Fl. July.