So let's start with some terminology. I think this sometimes can trip people up.
European hops (Humulus lupulus var. lupulus) are dioecious, herbaceous, rhizomatous, climbing, perennials.
Dioecious - This is greek for "two houses". Quite literally, male and female flowers are on separate plants, generally resulting unisexual plants.
Herbaceous - The plants do not form any (living) above ground woody tissues, this resulting growth dies every year. Yes, I understand the crown gets woody, but I am making a distinct difference between the crown and the bines.
Rhizomatous - The plant forms rhizomes (duh!), but let's make the distinction right now, rhizomes ARE NOT roots! Rhizomes are a modified underground stem. A stem, analogous to the green stem growing above ground. A rhizome must FORM both new roots and new shoots (from buds). A root must form new shoots, as it already has roots and contains the ability to uptake water. People, if this doesn't make sense, just ask.
Perennial - To most of us this should be an obvious one. The plant is long-lived, surviving multiple years depending on the overall health. Reports of 50-70 years have recorded.
There are five genetically distinct subvarieties of H. lupulus. They include: var. lupulus, var. neomexicanus, var. lupuloides, var. cordifolius, var. pubescens. These are based on their different morphological characteristics.
There are three species contained within the Humulus genus. The include H. lupulus (as listed above.), H. japonicus synonymous with H. scandens (the annual Japanese hop), and H. yunnanensis (the perennial Chinese hop).