164 HUMULUS LUPULUS. 
The genus Humulus, which has only a single 
species, is found in the Linnean class Diecia, 
and order Pentandria. It belongs to the natural 
orders Scabride, Linn. and Urtica, Juss. Its 
barren flowers haye a calyx of five leaves and 
no corolla. ‘The fertile flowers have for their 
calyx the scales of an ament, each two flowered ; 
corolla of one petal, lateral; styles two; seeds 
solitary, invested with the corolla, 
The Hop vine is an ornamental plant, much 
more frequently seen cultivated than wild, and 
climbing to a great height. The root is peren- 
nial. Stems annual, twining from right to left, 
angular, rough, with minute reflexed prickles. 
Leaves opposite, on long winding petioles, the 
smaller ones heart-shaped, the larger ones three 
or five lobed, serrated, veiny and extremely 
rough. Flowering branches axillary, angular 
and rough. Stipules two or four, between the 
petioles, ovate, reflexed. Flowers numerous, and 
of a greenish colour. Those of the barren plants 
are very numerous and panicled. Their calyx 
has five oblong, obtuse, spreading, concave leaves, 
Corolla wanting. Stamens short, the anthers 
oblong, and bursting by two terminal pores, 
The fertile flowers, growing on a separate plant, 
are in the form of an ament, haying each pair of 
