Nature · Ferns, grasses & other plants

Mistletoe

Evergreen hemiparasite · berries December–February

Viscum album — Santalaceae

Mistletoe is a hemiparasite: it has green leaves and photosynthesises for itself, but sinks a specialised organ, the haustorium, into a branch of its host to steal water and minerals. It grows into a leafless-looking green ball high in the canopy of apple, lime, hawthorn and poplar, and is famously rare on oak. Male and female plants are separate, so only the females carry the white berries, whose flesh is so sticky that birds wipe the seeds onto the next branch and plant them.

How to spot them

▸A dense spherical bush high in a bare winter canopy, still green when the tree is not
▸Forked branching in neat pairs, each fork bearing two opposite leathery yellow-green leaves
▸Translucent white berries in tight clusters, only on female plants, ripening midwinter
▸No contact with the ground at all — it is rooted into a branch, not the soil
▸Commonest on apple in old orchards, then lime, hawthorn and poplar; scarce on oak

How to know it

A hemiparasite: green and photosynthetic, but sinking a haustorium into a branch for water and minerals

Mistletoe.

Male and female plants are separate, so only some bushes carry the white winter berries

Mistletoe — it is dioecious.

Its berry flesh is so glutinous that birds wipe the seeds off their beaks onto the next branch, planting them

Mistletoe; the bird that gave its name to the plant is the mistle thrush, though blackcaps matter more.

Pliny describes druids cutting it from oak with a golden sickle, which is why its rarity on that tree is remarkable

Mistletoe.

In Norse myth it is the one thing Frigg failed to make swear an oath, so Loki had it made into the dart that killed Baldr

Mistletoe.

Its British stronghold is the old cider orchards of the Severn Valley, Herefordshire and Worcestershire

Mistletoe.

Its Latin generic name is the source of the words viscous and viscid, and of the birdlime once made from its berries

Viscum album.

Quick-fire facts

•A hemiparasite, not a full parasite: it photosynthesises but takes water and minerals from the host through a haustorium
•Now placed in the sandalwood family Santalaceae, after long being given its own family, Viscaceae
•Dioecious — male and female flowers on separate plants — so only female bushes bear berries
•The seed is spread by birds, above all the blackcap in Britain, which wipes it onto bark, and by the mistle thrush
•Viscum gives English viscous and viscid; birdlime was made from the berry pulp
•Rare on oak, which is exactly why the druidic oak mistletoe of Pliny's Natural History carried such prestige
•British stronghold is the Severn Valley and the old orchards of Herefordshire, Worcestershire and Gloucestershire; Tenbury Wells holds a mistletoe auction
•In the Prose and Poetic Edda, mistletoe is the weapon that kills Baldr
•The berries are toxic to people if eaten in quantity, despite being a bird food

Drill it — 8 cards

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Sources

Woodland Trust — Mistletoe (Viscum album)