From Wikipedia, the free encyclopedia
Humulus, (Hop) is a
small genus of flowering plants native to temperate
regions of the Northern Hemisphere. The female flowers (often called "cones") of
H. lupulus are known as hops, and are used as a culinary flavoring and stabilizer, especially in the brewing of beer. The hop is part of the family Cannabaceae, which
also includes the genus Cannabis (hemp).
Description
Although frequently referred to as the hop "vine", it is
technically a bine; unlike vines, which use tendrils, suckers, and other
appendages for attaching themselves, bines have stout stems with
stiff hairs to aid in climbing. It is a perennial herbaceous plant which sends up new
shoots in early spring and dies back to the cold-hardy rhizome in autumn. Hop shoots
grow very rapidly and at the peak of growth can grow 20 to 50
centimetres (8 to 20 in) per week. Hop bines climb by wrapping
clockwise around anything within reach, and individual bines
typically grow between 2 to 15 metres (7 to 50 ft) depending
on what is available to grow on. The leaves are opposite, with a 7 to 12 cm (2.8
to 4.7 in) Petiole and a cordate-based, palmately lobed blade
12 to 25 cm (4.7 to 9.8 in) and broad; the edges are
coarsely toothed. When the hop bines run out of material to climb,
horizontal shoots sprout between the leaves of the main stem to
form a network of stems wound round each other.
Male and female flowers of the hops plant develop on separate
plants (dioecious). Female plants, which
produce the hops flowers used in brewing beer, often are propagated
vegetatively and grown in the
absence of male plants. This prevents pollination and the
development of viable seeds which
are considered undesirable for brewing beer.[1]
Species
There are three species, one with five varieties:
- Humulus japonicus (syn.
H. scandens). Asian Hop. Leaves with 5–7 lobes. Eastern
Asia.
- Humulus
lupulus. Common Hop. Leaves with 3–5 lobes. Europe, western Asia, North America.
- Humulus lupulus var. lupulus. Europe, western
Asia.
- Humulus lupulus var. cordifolius. Eastern
Asia.
- Humulus lupulus var. lupuloides (syn. H.
americanus). Eastern North America.
- Humulus lupulus var. neomexicanus. Western
North America.
- Humulus lupulus var. pubescens. Midwest North
America.
- Humulus yunnanensis. Yunnan Hop. Leaves with 3–5
lobes, densely hairy below. Southeast Asia (endemic in Yunnan, China).
Brewers' hops are specific cultivars, propagated by asexual
reproduction: see List of hop varieties.
Hop
varieties
References
- Lee W. Janson, Ph. D.; Brew Chem 101; Storey
Publishing; ISBN 0-88266-940-0 (paperback, 1996)
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