Humulus japonicus
Humulus lupulus
houblon japonais, Japanese hop, Japanese hop(s)
common hop, common hop(s), European hop, hop, hop(s), houblon
blade cordate, palmately 5-9-lobed, 5-12 cm, margins of lobes serrulate, apex acuminate;
surfaces abaxially with veins pubescent, with stiff hairs, glands yellow, sessile, discoid, adaxially margins of younger leaf blades with stiff cystolithic hairs.
blade ± cordate, palmately 3-7-lobed, sometimes unlobed, 3-15 cm, margins dentate-serrate;
surfaces abaxially with veins glabrous or with soft pubescence, without straight, erect hairs, glands yellow, adaxially margins of younger leaf blades with few or no cystolithic hairs.
staminate inflorescences erect, 15-25 cm, flower anthers without glands; pistillate inflorescences spikes, conelike, ovoid;
bracteole ovate-orbiculate, 7-10 mm, pilose, margins densely ciliate-hairy.
staminate with flowers whitish to yellowish, anthers glandular; pistillate usually racemes, 10-20 mm, pedunculate;
bracteole margins not ciliate-hairy.
pendulous, green, conelike, ovoid to oblong, (1-)1.5-3(-4) cm;
bracteoles without yellow glands.
pendulous, pale yellow, conelike, ovoid to oblong, (1-)2-3(-6) cm;
bracteoles with yellow glands.
yellow-brown, ovoid-orbicular, inflated to lenticular, 4-5 mm, glandless.
yellowish, ovoid, compressed, glandular.
= 20, including 6 chromosomes concerned with sex determination.
= 20, including 2 or more sex-determining chromosomes.
Humulus japonicus
Humulus lupulus
Although I have no records from New Hampshire, the state is within the geographic range of Humulus japonicus.
Variegated forms of Humulus japonicus, cultivated as ornamentals, are sometimes spontaneous. The vernacular name Japanese hop(s) is occasionally misapplied to H. lupulus var. cordifolius (Miquel) Maximowicz, a variety not found in North America.
The disposition of the name Humulus scandens (Loureiro) Merrill, based on Antidesma scandens Loureiro, is problematic. E. D. Merrill (1935) was convinced that the name A. scandens applied to the species Humulus japonicus. If Merrill was correct, then the combination Humulus scandens would have priority. The material described by Loureiro, however, was not preserved, and his description does not coincide with that of H. japonicus. Humulus scandens is not included in synonymy in this treatment.
I. A. Grudzinskaya (1988) segregated Humulus japonicus as a new monotypic genus, Humulopsis, with the single species Humulopsis scandens (Loureiro) Grudzinskaya.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 5 (4 in the flora).
Humulus lupulus has often been transplanted from the wild to homesites as an ornamental. When such sites are abandoned, the plants often persist, and it may appear that they are present naturally. As well, suppliers of ornamental plants may sell hops collected from one site to buyers in a quite distant site. The hop varieties discussed here may therefore be found occasionally beyond the distribution ranges given in this treatment.
Native Americans used Humulus lupulus medicinally to induce sleep, for breast and womb problems, for inflamed kidneys, rheumatism, bladder problems, intestinal pain, fever, earaches, pneumonia, coughs, and nervousness, as a tonic and a stimulant, and as a witchcraft medicine (D. E. Moerman 1986).
The measurements mentioned in couplet 1 of the following key are taken in the middle abaxial portion of the central lobe on 4-6 cm leaf blades attached to flowering or fruiting twigs.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaf blades usually with fewer than 20 hairs per cm on length of midrib, fewer than 25 glands per 10 sq. mm between veins; nodes relatively limited in pubescence, usually fewer than 15 hairs per 0.1 sq. mm at most pubescent portion (excluding angle of petiole with stem). | var. lupulus |
1. Leaf blades usually with more than 20 hairs per cm on length of midrib, more than 25 glands per 10 sq. mm between veins; nodes relatively pubescent, usually more than 15 hairs per 0.1 sq. mm at most pubescent portion (excluding angle of petiole with stem). | → 2 |
2. Leaf blades 10 cm or more usually having at least 5 lobes; smaller blades (ca. 5 cm) usually with more than 3 easily visible veins branching off midrib (excluding proximal branches). | var. neomexicanus |
2. Leaf blades 10 cm or more usually having fewer than 5 lobes; smaller blades (ca. 5 cm) often with no more than 3 easily visible veins branching off midrib (excluding proximal branches). | → 3 |
3. Leaf blades conspicuously pubescent abaxially, more than 100 hairs per cm on length of medial midrib, hairs present between veins. | var. pubescens |
3. Leaf blades not conspicuously pubescent abaxially, usually fewer than 100 hairs per cm on length of medial midrib, hairs usually absent between veins. | var. lupuloides |
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OR, 
WA - Local Web sites: CalFlora, CalPhotos,
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MI Flora, 
MN Wildflowers, 
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PNW Herbaria 
WildflowerSearch
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USDA Plants Database- LBJ Wildflower Center
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