Grass of Parnassus, Parnassia palustris

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Grass of Parnassus, Parnassia palustris

Early Autumn is here, a combination of warm sunny days and some rain.

We’ve taken the advantage of recent drier weather to do more trips, including visits to Beeston Common, near Sheringham, in North Norfolk. It’s an hour’s train ride from Norwich and its valley mire is the home of some lovely plants, including Grass of Parnassus.

Grass of Parnassus, Parnassia palustris, is one of the treats of autumn. It grows in wet places, such as base-rich flushes in bogs, short grassland and valley mires. In the British Isles it has a mostly northerly distribution, though that is due to the lack of habitat further south, especially as land has been drained and “improved”. It grows near sea level (var ‘Condensata’) on the machair of western Scotland and in Lancastrian and Cumbrian dune slacks, but also up to 1000 metres (3000 feet) on mountains, such as Ben Lawers in Perthshire. Further afield, it occurs in northern parts of continental Europe, northern and central Asia, North America and parts of North Africa.

Parnassia palustris isn’t really a grass (family Poaceae), but a member of the Celastraceae, the Staff-vine family. Most members of this family grow in the tropics but Spindle (Euonymous europeaus), which I wrote about in October 2012, is in also in this family. (As we learn more about relationships between plants, they are sometimes reclassified into different families. When I did Botany at university, Parnassia palustris was considered to be a member of its own family, the Parnassiaceae, and before that it was considered to be a member of the Saxifragaceae.)

Grass of Parnassus is a perennial plant and early in the summer you’ll only find its basal leaves. But from July or August (sometimes even late June) the plant will produce exquisite white buds atop flower stalks, which grow from 10 to 30 centimetres tall. The flowers open in late summer to early autumn, over several weeks. They are beautiful and very memorable: each flower has five white petals, with strong, translucent grey-green veins. On a still, warm day the flowers have a very delicate, honey scent.

Each flower is hermaphrodite, that is, it has both male and female reproductive parts. At the centre of the flower are the female parts: the pistil, made up of four fused carpels, with a very short style branching into four stigmas. These are surrounded by five three-pronged sterile stamens. Each of these is tipped with drop-like, false nectaries, which (along with veins on the petals) help to attract pollinating flies and bees.

The Finnish NatureGate website describes how the plant produces its nectar to attract pollinating insects. The Wildflower Finder website has a series of excellent photographs showing the flowers and the development of seedheads. The seeds are easily spread by wind and water. They are small and light (30 micrograms each) and have an air-filled pouch that helps them to float.

With its exquisite flowers,Grass of Parnassus has inspired poetry. Andrew Lang (1844 – 1912), writing of the plant in Galloway in southern Scotland, referred to the plant’s “returning snow / Between September and October chill” in his poem “Grass of Parnassus“. Plantlife describe it as “A flower of cold beauty and a symbol of ‘the wilderness and wet'” and NatureGate’s description of the plant’s habitat is very lyrical: “Grass of Parnassus grows where cool air flows in low peatland meadows and wetlands which get easily misty and catch the first night frosts.”

Parnassia palustris is the county flower of both Cumbria and Sutherland, and appears on the Cumberland flag.

One of the alternative names for the plant is ‘Bog-star‘, which is nicely descriptive. (Sometimes this is written as ‘Bog star‘.) The plant’s Latin name, Parnassia, was coined by Linnaeus. This and the ‘Parnassus’ in the English name both refer to Mount Parnassus in Greece. In ‘Flora Britannica‘, Richard Mabey traces the name Grass of Parnassus back to 1576 when the Flemish botanist Matthias de l’Obel* used the name ‘Gramen Parnassi’, which Henry Lyte translated into English in 1578.

The First Nature website suggests why ‘Grass’ is part of the name: it could be because the veins on the petals resemble grass leaves or because cattle on Mount Parnassus enjoyed eating the plant as if it were a grass. More certain and very apt is that ‘palustris‘ refers to the wetlands where the plant can be found.

Grass of Parnassus is not noted for being edible, though the Plants for a Future website describes some of its possible medicinal uses.

I leave you with another photograph of this exquisite plant, and a tip for photographers: take your photographs on an overcast day or shade the flowers. Bright sunshine bounces off the white petals and photographs will be bleached out. Oh, and wear boots or even wellies.

Grass of Parnassus

Photograph by Vanna Bartlett.

*The genus Lobelia is named after him.

Spanish Catchfly, Silene otites

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Summer ended early this year and September has been cold and wet here in Norfolk. This summer’s last hot, sunny days were at the end of August and on one of the hottest of these days (August Bank Holiday, 28th August 2017) we visited the Norfolk Brecks with our friend Ian. We took a train from Norwich to Brandon and a taxi to Cranwich Camp, and then walked back to Brandon station on some lovely tracks and paths.

One of the plants we had gone to see at Cranwich Camp was Spanish Catchfly, Silene otites.

Spanish Catchfly

Spanish Catchfly, Silene otites, at Cranwich Camp.

Spanish Catchfly, Silene otites, is a member of the Carnation family, the Caryophyllaceae. Silene is the biggest genus in the family, with around 700 species, and in the British Isles it includes the Campions and several other Catchflies. Silene is named after Silenus, a woodland deity in Greek mythology, companion and tutor to the wine god Dionysus.

Spanish Catchfly is a rare native plant in the British Isles, and it is a speciality of Breckland, where it grows on grass heaths and, in Suffolk, on some roadsides. Cranwich Camp, an area of SSSI grassland in west Norfolk, west of Mundford and south of the village of Cranwich, is one of the best places to see it. A Labour camp was set up on the site in 1935 and unemployed men from the north of England were housed there and made to do manual work in exchange for dole money. In World War Two the camp was used by the armed forces. In more recent years, the site was notified as a Site of Special Scientific Interest (SSSI) because it is home to several rare invertebrates and plants. The latter include Spanish Catchfly and Proliferous Pink.

Spanish Catchfly is a perennial plant, which forms a rosette of narrow, dark green leaves. Tall, narrow spikes of tiny, lacy, cream-coloured flowers occur from June to September – when we were there in late August, some had run to seed but others were still in bud. The plant is more or less dioecious – there are separate male and female plants, though the male plants sometimes bear a few hermaphrodite flowers, usually with only a vestigial ovary.

Silene otites - male flowers

Male flowers

Female plant - Silene otites

Female plant with seed capsules

Like several of its relatives, Spanish Catchfly has scented flowers, especially after dusk. Night-flying moths and mosquitoes are the main pollinators and the flowers emit a range of chemicals to provide their scent. It has been suggested that Catchflies’ sticky hairs may have evolved to prevent the theft of pollen by wingless insects climbing the stems.

Silene otites does best in an open grass sward. In denser grassland, the plants are eventually crowded out and the seedlings need disturbed ground to establish successfully.

Until the late 1990s there were thousands of Spanish Catchfly plants at Cranwich Camp, but a survey in 2007 found only 221 plants. Something had to be done and in 2011 turf was stripped from part of the site. The experiment was a success: by 2013 over 2900 plants were recorded in the stripped area. Spanish Catchfly was certainly abundant when we visited Cranwich Camp in August.

Spanish Catchfly is widespread throughout Europe and it is fairly common in eastern, central and southern Europe but very local in the northern parts of its range, including the British Isles. In the west its distribution extends from Iberia northwards to Britain, while the eastern edge of its range extends to Poland, the Caucasus, northern Iran and Siberia.

Sea Pea, Lathyrus japonicus

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Sea Pea, Lathyrus japonicus

Sea Pea, Lathyrus japonicus, at Shingle Street (29th July 2017).

Last month we were given a lift to Shingle Street in Suffolk, a tiny hamlet at the mouth of the River Ore. It must be bleak in winter, but on a sunny day at the end of July it was a lovely place to visit. We saw several species of butterflies, including a couple of Clouded Yellows that swept past on a south-westerly wind. Most impressive, apart from the sheer amount of sky and fresh air, were the plants. These included big clumps of Sea Kale, Crambe maritima, and large patches of Sea Pea, Lathyrus japonicus.

Sea Pea, Lathyrus japonicus, is a a member of the Pea family (Fabaceae). It is long-lived perennial herb that grows on shingle beaches and, occasionally, blown sand, where it is one of the first plants to colonise. Good places to see it include Shingle Street and Orfordness in Suffolk and Rye Harbour in Sussex. It is usually in flower from late May until late July. The flowers are followed by seed pods, green at first, ripening to dark brown. By late summer the plants start to die back, leaving dry stems without leaves, which can persist through early winter. Stems show above the ground again from April.

Sea Pea is a very distinctive plant. Its trailing stems grow up to 50 to 80 centimetres (cm) long and bear waxy, glaucous green pinnate leaves, five to ten cm long, with two to five pairs of leaflets. The terminal leaflet is often replaced by a twining tendril. The large flowers are produced by plants that are three or more years old. They have a dark purple standard petal and paler purple wing and keel petals. They are produced in racemes of up to twelve flowers. There are some lovely photos on the NatureGate and Seasonal Wild Flowers websites. The flowers are pollinated by long-tongued bumblebees such as Bombus pascuorum, B. hortorum and B. lapidarius.

Bombus pascuorum on Sea Pea flowers.

Bombus pascuorum (Common Carder-bee) on Sea Pea flowers.

Sea Pea’s stronghold in the British Isles is East Anglia but there are isolated colonies in Angus on the east coast of Scotland and even on Unst in Shetland (see map). It is classified as being of “Least Concern” in the Vascular Plant Red Data List for Great Britain. R.E. Randall has written about its past and present status and distribution in the British Isles in in Watsonia vol. 11, pp 247 – 251 (1977).

Lathyrus japonicus is also found on the coasts of Denmark and Norway and, in Sweden and Finland, on coasts by the Baltic Sea, the Gulf of Finland, Gulf of Bothnia and beside Lakes Ladoga and Oneda in Russia. It also grows in parts of Greenland and Iceland, in Eastern Siberia through Kamchatka to Japan (on sand dunes) and on the western coast of North America from northern California to Alaska and on the east coat from Newfoundland to Long Island, the lower St. Lawrence River and the Great Lakes (see p28 of “Shingle Biodiversity and Habitat Distrurbance” by E. J. Low). It is now extinct in northern France.

Lathyrus japonicus is a tough plant, especially once it is fully grown. Although seedlings are susceptible to drought, both mature plants and seedlings are frost resistant. A covering of 15 cm of shingle can kill younger plants, but older ones can produce axillary shoots on their stems, which can grow almost vertically up through as much as 40 cm of blown sand (Low p31). Mature plants can also regenerate from short sections of rhizome after storms. The seeds are light and buoyant and are viable for at least five years, meaning that they can be dispersed on the tides. Visitor pressure may be one of the biggest threats to the plant – repeated human footfall can damage the plant – but at Shingle Street it seems to be thriving.

Stock Doves and Wood Pigeons sometimes eat Sea Pea seeds and may help to disperse them – this probably accounts for a big increase in the plant at Rye Harbour in the 1960s. Sea Pea is also one of the foodplants of the micro moth Pima boisduvaliella, which flies on warm summer evenings. The weevil Bruchus loti emerged from seeds collected at Rye Harbour in 2003 (Low p32).

Sea Pea seeds have been eaten by humans, especially in times of famine, including at Aldeburgh in Suffolk.The Plants for a Future website says that the seeds are said to be safe and very nutritious in small quantities, but should not comprise more than 30% of the diet. The note of caution is well advised. The seeds contain the neurotoxin oxalyldiaminopropionic acid (ODAP), which can cause lathyrism, a condition involving degenerative changes to the spinal cord, leading to paralysis and lack of strength in or the inability to move the lower limbs.

Lathyrism is more usually associated with the Grass Pea, Lathyrus sativus, a tasty and nutritious crop grown for food for humans and livestock in East Africa and parts of Asia. Advice from Kew Gardens is that Grass Pea is “harmless to humans in small quantities” but it should not be eaten in larger amounts over an extended period of time. Some Western Asian varieties of Grass Pea have been bred to contain lower amounts of ODAP, but the chemical is thought to be of benefit to the plant, helping it cope with drought and waterlogging.

It is because of Sea Pea’s fairly restricted distribution and the slight risk of lathyrism from eating the seeds that I have included it in the “Ornamental” rather than “Edible” category on my blog.

Update 18th March 2018:

When we visited Shingle Street, we noticed the line of shells on the beach. I  have just discovered why they are there: “Shingle Street shell line inspired by friends’ cancer treatment“.