Botanical Illustration: Telling Gorse species apart

Story posted: Thursday, 6. April 2017 by Lizzie Harper

Whilst working for The Field Studies Council on charts of Heathland and Wayside plants, I needed to illustrate the three species of Gorse (Ulex) found in Britain.

Gorse is a shrubby, spiny family of plants in the pea family with spiny green prickles or spines and bright yellow flowers.  Young plants have trifoliate leaves (slightly resembling elongate clover leaves), but on mature plants these disappear leaving the spines and the flowers.

Lizzie Harper botanical illustration painting of gorse Ulex in progress

Painting of Gorse with specimens

All three of these plants are found on heathland and acidic soils, but their distribution and flowering times can help in telling them apart.  They are Common gorse or Furze (often simply called “Gorse”)  Ulex europeaus, Western gorse Ulex gallii, and Dwarf gorse Ulex minor.

Common gorse or Furze, Ulex europaeus

This plant is very common and widespread across heathland, coastal areas, road verges, and wasteland.  It commonly grows up to 2m high, and can reach 3m.  It likes acidic soils, but can be found on chalky cliffs (unlike the other gorses).

The spines on Common gorse are very firm and rigid, deeply furrowed, and a slightly blueish dark green.  They’re 1-3cm long.  The plant is evergreen with slight black hairs on the stem.  It’s a densely spiny plant and forms impenetrable thickets.

Lizzie Harper Natural history natural science botanical illustration sciart illustrator blog on gorse  ulex species

Looking at the flower, the bracteoles are more than twice the width of the pedicel (flower stem), which are larger than in other gorse species.  Flowers are a rich bright yellow, with the keel of the flower slightly shorter than the wings on either side.  The calyx (up to 3cm) is 2/3 the length of the corolla and can be yellow, but tends to be a pale green.  U. europeaus also has a very distinct (and lovely) smell of coconuts to its flowers, I always think it smells of tropical beach holidays, especially when the sun is beating down on the yellow flowers.  The calyx is yellow green and has spreading hairs.

However, the big distinction is the time of flowering.  It’s no coincidence that the Oxford Dictionary contains the phrase, “When the gorse is out of bloom, kissing is out of season”, U.europaeus flowers from January to June (a six month flowering season, with occasional flowering outside of these times) and the other species flower from July through late November.

The fruit are purpley brownish pea pods, about 20 mm long, each containing a few shiny black seeds (which are said to be viable for up to 30 years).  The remnants of the calyx remains around the pod.

Common gorse has long been used for hedging and setting boundries, has been cultivated for gardens, and was sometimes bruised with stones before being fed to horses and livestock.  As with other gorses, it can survive fire.  Common gorse is used in medicine as it produces Lectin, a protein that specifically binds to H-substance receptor sites on human red blood cells, and thus is used as a test to show people lacking these sites (an unusual condition called “Bombay Phenotype”). – US National Institutes of Health

Western gorse Ulex gallii

Western gorse is smaller and more compact than the Common gorse, growing up to 1.75m high, and thrives on cliff tops, old pasture, heath and coastline shingle.  Its range is across the West of the UK, and East Anglia, but no further north than Solway, and isn’t found higher up than 670m.

Western gorse spines seem to crowd more densely around the main stems than with Common gorse, and these are furry with reddish brown hairs.  The spines are rigid, but far less deeply grooved than with Common gorse, and a slightly yellower hue.  This makes the smaller clumps of Western gorse seem less blue than Common gorse.

Lizzie Harper botanical illustration Western gorse Ulex galliii

The flowers are a deep yellow (darker than those of Common gorse), with yellow bracteoles bearing flattened hairs.  These are less than twice as wide as the pedicels, and 0.5mm long.  The calyx (9-13mm) extends up to ¾ of the length of the corolla, and the teeth of the calyx meet.  Unlike the Common gorse, the wings of the flowers of Western gorse are longer than the keel.

The flowers are out from July through November, and this is the main way to tell the two species apart.

Fruit are borne in brown pods, and remnants of the flower are often present.

Western gorse is used in many of the same ways as Common gorse, and is similarly good for wildlife, providing nesting habitats for birds, and flowers for insects.

Dwarf gorse Ulex minor

This gorse is far easier to tell apart than the other two species.  It is only found in the South and South east of the UK and is a much smaller plant both in habit and in detail, rarely growing higher than 1m.  It often is procumbent and low growing.  It likes acidic sandy heaths, and is very local in distribution, found only in SE England.

The spines of Dwarf gorse are smaller and far less rigid than the other two species, are not striated or furrowed, and can be slightly curved.  Spines crowd tightly together around the stem, making it hard to see the stem below.  The stems have brown hairs.

Lizzie Harper botanical illustration of Dwarf gorse Ulex minor

Flowers of Dwarf gorse are yellow, with a calyx (5-9mm) almost as long as the corolla. Bracteoles bear flattened hairs and are less than twice as wide as the pedicels, and 0.5mm long.  The calyx is yellow, with appressed hairs, and has divergent teeth (unlike in U. gallii).  The wings and keel of the flower are a similar length.

Fruit are borne in pods, as Ulex are in the pea-family, and as with the other species the pods turn from a pale green to a brown, contain dark brown seeds and often bear remnants of the flower.

The take home message is that the easiest way to tell Common gorse and Western gorse apart is to see when they’re in bloom; there are other ways, as described, but this tell-tale feature is by far the easiest (though not 100% foolproof) method for a swift identification.

References for this piece include feedback from the botanists I collaborated with to produce the illustrations for Field Studies CouncilStreeter’s Collins Flower Guide, Stella Ross-Craig’s amazing illustrations,  the websites of the Wildlife TrustsUK Wildlfowers, and other useful links (see below).

Ryedale Natural History Society

ispot forum on telling gorse apart

RSPB Gorse for wildlife

Wild Flower Society

 

 

On another topic entirely, I'm afraid I've had to turn off the "comments" button on my blogs due to spamming.  If you would like to give any comments or feedback, please do so on my Facebook page or Twitter account or email me at info@lizzieharper.co.uk.  Many many thanks; and apologies

 

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