Jeremy Bartlett's LET IT GROW blog

The wonder of plants and fungi.

Piggyback Rosegill, Volvariella surrecta

Posted on 28 October, 2017 by Jeremy Bartlett22 November, 2021

“Great fleas have little fleas upon their backs to bite ’em, And little fleas have lesser fleas, and so ad infinitum.” – Augustus De Morgan, based on a verse by Jonathan Swift.

Piggyback Rosegill, Volvariella surrecta

Previously I have written about parasitic plants such as Mistletoe, Ivy Broomrape and Purple Broomrape. Piggyback Rosegill, Volvariella surrecta, is a parasitic fungus, which grows on the caps of another fungus. In the photograph above, the smaller, button-like fungus is the Piggyback Rosegill and it is feeding on the decaying bigger fungus underneath it.

Piggyback Rosegill’s host is the Clouded Funnel, Clitocybe nebularis, a very common fungus that can be found in both broadleaved and coniferous woodland and at the bottom of hedgerows. It is saphrotrophic, obtaining the nutrients it needs from decaying organic matter. Clouded Funnels have a slightly funnel shape when mature and are usually grey, sometimes with a cloud-like pattern in the centre, hence the English name. They often grow in large fairy rings.

Clouded Funnels, Clitocybe nebularis.

Piggyback Rosegill can apparently grow on other species of fungus as well (species of Tricholoma, the Knights), but this is very rare.

On the Scottish Fungi website, Liz Holden discusses whether the Piggyback Rosegill is an obligate parasite (i.e. is it reliant on living Clouded Funnels?) or a host specific saprotroph (i.e. does it just feed on rotting Clouded Funnels?). She concludes that the truth “might be a bit of both“.

The Scottish Fungi website uses an alternative English name, Piggyback Pinkgill. Volvariella surrecta has free, broad and crowded gills, which are white in younger specimens before turning pink as the spores mature, to give the fungus its English names. The First Nature website has further information to help with identification, and some good detailed photographs.

Some fungi don’t produce their fruitbodies every year but in my experience Clouded Funnel is a reliable performer, putting in an appearance every autumn in the places where I’ve found it.

In contrast, Piggyback Rosegill is described as “uncommon to rare” (Sterry and Hughes 2009) and “tends to turn up with any regularity only in a few places” (Marren 2012). The First Nature website says it is a rare sight in Britain and Ireland, mostly found in southern England. The Carmarthenshire Fungi website describes a sighting from Wales and the species has been seen from at least one site in Scotland. Further afield it has been recorded from many other European countries, North Africa, parts of North America, and New Zealand. In the Norwich area it had only been sighted at Colney Woodland Burial Ground and on Mousehold Heath, but within the last week we have found it in Earlham Cemetery on a fungus walk and in Train Wood. 2017 seems to be a good year for finding it.

Clouded Funnels can be found from August to early December and Piggyback Rosegills are normally found in October and November.

Piggyback Rosegill in Train Wood, Norwich

Thanks to James Emerson for identifying the latest Piggyback Rosegills in Norwich.

Grass of Parnassus, Parnassia palustris

Posted on 29 September, 2017 by Jeremy Bartlett2 October, 2017

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.

Photograph by Vanna Bartlett.

*The genus Lobelia is named after him.

Spanish Catchfly, Silene otites

Posted on 16 September, 2017 by Jeremy Bartlett29 January, 2018

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, 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.

Male flowers

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.