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Primitive Plants and Ice Age Survivors: around Beverley in July

A scarce find in our area, this Adder’s-tongue (Ophioglossum vulgatum) lurked beneath a

few hawthorns on Figham Common, hiding from the tongues of grazing horses and cattle. A

vestigial plant of our once-widespread damp meadows, it’s a fern, though without its spore-

bearing spikes you’d never guess. One of the peculiarities of this odd plant is its huge

number of chromosomes, the highest of any plant in Britain (over a thousand to our 46).

This tells us it’s an ancient plant, but also that with this amount of ‘junk’ DNA it may be an

evolutionary dead end, close to extinction. To herbalists it was known for centuries as a

wound herb, called the ‘green oil of charity’.

Unsurprisingly with a plant this weird, it’s been a favourite in witchcraft, reputedly useable

to stop slander and gossip.

Some herbalists used the plant below, Horsetail, in poultices with Adder’s-tongue. It too is

ancient, its giant ancestors forming huge forests in Carboniferous times. This variety is

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Water Horsetail (Equisetum fluviatile), bearing its spores at the tips of its shoots. This is in

the Leven Canal.

The Horsetails above are often

confused with Mare’s-tails (Hippuris

vulgaris) left, which also grow in the

canal, but the latter are in

evolutionary terms much younger

as they are flowering perennials,

although the flowers are tiny and

inconspicuous.

The Leven Canal is one of our most

interesting local wildlife sites. It’s

maintained now as an SSSI by

Natural England. The dominant

reedbeds are dredged to allow the

canal to survive as a watercourse,

though unused since 1935 and no

longer navigable.

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It’s believed the canal was

cut through the site of

former meres, leftovers

from the Ice Age, and some

of the vegetation may be

relict from when the

glaciers melted. It’s a

brilliant ribbon of diversity.

The White Water Lily

(Nymphaea alba) is a

primitive plant, and an ice

age survivor, happy rooting

in the clean, sluggish water.

The Nymphaea alba despite being one of the earliest flowering plants to evolve, has a

complex relationship with its pollinators. On its first day of flowering, it produces nectar

and the stigma are receptive to pollinating insects from another lily. Overnight the petals

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close, trapping insects. By days two and three the nectar has dried up, the stigma are no

longer fertile and the insects escape, but not before picking up pollen from the stamens

which begin to fold inwards. Then after another day or two, the flower stem spirals it

underwater, where the seed pods form and are later released into the muddy canal bottom.

This is an example I found floating detached on the edge of the canal, which allowed me to

have a close look. This is a successful method of avoiding self-pollination.

One of the canal’s most intriguing plants is Greater Bladderwort (Utricularia vulgaris),

flowering in July. Unlike the White and Yellow Water Lillies, with their large floating leaves,

Bladderwort needs to supplement its diet. It’s our local carnivorous plant, with the fastest

trapping mechanism known in the plant kingdom. Underwater are the ‘bladders’, small

pouches which close incredibly fast to trap aquatic prey. Once the prey is digested, the

bladders become vacuums again, ready to trap the next prey by suction, triggered by tiny

hairs. They feed on small crustaceans, water fleas, nematodes and even tadpoles.

Left: Bladderwort’s underwater trapping

‘bladders’.

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Above: the yellow flowers of Greater Bladderwort. The ‘flask’ at the bottom right is a seed

capsule of Yellow Water Lilly (Nuphar lutea), which carries the seeds downstream.

Left; Yellow

Loose-strife

(Lysimachia

vulgaris)

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Yellow and Purple

Loosestrife

(Lythrum salicaria),

left, grow here

together, but

despite sharing

English names they

are unrelated.

They both attract

many pollinators.

Lesser Burdock (Arctium minus), left,

which you might remember as an

ingredient of Dandelion and Burdock

(nowadays mostly synthesised), is

another insect-magnet by the canal,

as are other members of the

maligned thistle family.

The Creeping Thistle (Cirsium arvense) was classified by the

1959 Weed Act as ‘injurious’. To agriculture maybe, but not

to the natural world where its nectar is highly attractive to

insect pollinators.

Left: a Green-veined White feasts on Creeping Thistle

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Here a Comma butterfly feeds on the nectar of Creeping Thistle. The name ‘Comma’ derives

not from the curved wings, as I used to think, but from the ‘C’ shape on the underwing.

Left: the Comma underwing

showing the small white

comma shape.

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Above: Peacock on Spear Thistle (Cirsium vulgare)

The inconspicuous blue

Skullcap (Scutellaria

galericulata) grows here. It’s

one of the many riverside

plants with long medicinal

associations, especially for

anxiety. Its old common

name, however, is due to its

resemblance to a medieval

leather helmet. It’s a member

of the mint family.

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The striking Large-flowered Hemp Nettle (Galeopsis speciosa) is another unusual and now

scarce inhabitant of the banks.

Above left: Common Darter on the footpath

Above right: ovipositing Brown Hawker

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Above: Common Club-rush (Schoenoplectus lacustris) grows abundantly along the canal.

These used to be known locally as ‘dumbles’. They were used for matting, horse collars and

hassocks.

The area around these carrs, now drained and fertile farming land, once was rich wetland

supporting people with fish, wildfowl, reeds, peat, eels, and many plants for food and

medicine. We know that people were here from at least Mesolithic times, because they

have left their hunting tools and weapons in the marshes. Now it’s a peaceful oasis of

diversity. Don’t miss it.

HK July 2020