Bindweed Rust, Puccinia convolvuli

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Puccinia convolvuli

Bindweed Rust, Puccinia convolvuli. View of the fungus on the upper surface of Hedge Bindweed leaves (Calystegia sepium).

Bindweed Rust, Puccinia convolvuli

Bindweed Rust, Puccinia convolvuli. View of the fungus on the underside of Hedge Bindweed leaves (Calystegia sepium).

A week ago (11th September 2018) Vanna and I took the train to Woodbridge in Suffolk. It’s a lovely place to visit, with interesting old buildings, good pubs and independent shops and walks beside the River Deben. We visited the churchyard of St. Mary’s Church, to see a large and impressive nesting aggregation of Ivy Bees (Colletes hederae). There were masses of male bees flying low over the ground, looking for females emerging from nest holes. Each female was surrounded by a cluster of male bees, forming a mating ball, in which one lucky male was able to mate. A few females had already mated and were digging out their nest holes or flying off to nearby Ivy to collect pollen and nectar. We chatted with several visitors, who had seen us taking photographs and read printed signs thoughtfully put there to explain what the bees were doing.

After a pub lunch we walked down a footpath next to an Ivy covered hedge, on the hunt for more bees to photograph, but we were soon distracted. Near the start of the path there was a big patch of Hedge Bindweed, Calystegia sepium, and Vanna noticed that many of the leaves were covered in orange-brown pimples. On closer inspection these appeared to be some sort of rust, which we didn’t think we’d seen before.

When we came home I did an online search and found out from the excellent Plant Parasites of Europe website that the fungus was probably Puccinia convolvuli. Vanna also posted photos on Facebook, on the British Plant Galls site, and Malcolm Storey confirmed the identity of the fungus. Previous records in the UK have been of only a few pustules per leaf, rather than whole leaves covered in them.

Puccinia convolvuli has only recently been discovered in Britain and there have only been a handful of records so far, the first from near Weymouth in Dorset in 2009. I sent the details of our find to the Suffolk Fungi Recorder, Neil Mahler, and he confirmed that our sighting was the first record for Suffolk. Since we came home we’ve been looking at Hedge Bindweed here in Norwich, but haven’t seen any infected plants here yet.

Further afield, Puccinia convolvuli occurs in other parts of Europe and in Asia and North America. It will also infect other species of bindweed, including Mallow Bindweed (Convolvulus althaeoides), Field Bindweed (Convolvulus arvensis) and California Rose (Convolvulus japonicus, now known as Calystegia japonica).

Although Hedge Bindweed (Calystegia sepium) has lovely flowers, it is often a troublesome weed, as it grows very vigorously and has deep roots that are hard to dig out. As Puccinia convolvuli can cause extensive damage to the plant, it is not surprising it has been studied as a possible biological control of Hedge Bindweed. In his 1992 Masters thesis Jonathan Beener of Eastern Illinois University concluded that further investigation was worthwhile. (Beener, Jonathan C., “Evaluation of Puccinia convolvuli (Pers.) Cast. as a Biological Control of Calystegia sepium (L.) R. Br.” (1992). Masters Theses. 2118.). There have also been several studies biological control of bindweeds by another fungus, Phomopsis convolvulus, such as in the journal Weed Science (Morin, L., Watson, A., & Reeleder, R. (1989). Efficacy of Phomopsis convolvulus for Control of Field Bindweed (Convolvulus arvensis). Weed Science, 37(6), 830-835.)

Both Jonathan Beener’s thesis and the Phrygana website state that Puccinia convolvuli prefers growing in more humid places. This means that  growth of the fungus is restricted in more open situations (such as fields), which could limit its use as a biological control. It will be interesting to see how the fungus spreads throughout the British Isles, and whether it does better in wetter western areas.

Worldwide, Puccinia convolvuli is not the only rust that grows on bindweed. In 2003 a related species of Puccinia was identified in Japan, Puccinia calystegiae-soldanellae, growing on Sea Bindweed, Calystegia soldanella (Zhuang Li, Teruo Sano, Takashi Fujita, Fusaka Nakai, Yukio Harada (2004). Puccinia calystegiae-soldanellae, a new rust species on Calystegia soldanella from Japan. Mycoscience, 45 (3),Volume 45, Issue 3, pp200 – 205.)

When you go for a walk, keep an eye open for infected bindweed leaves and, if you find any infected with Puccinia, send a record (with photos) to your local fungi recorder. To help you, you can compare specimens with the excellent photographs of Puccinia convolvuli on the Plant Parasites of Europe website, Bioimages and Phrygana websites.

The photos on this page are by Vanna Bartlett.

Spring Sandwort, Minuartia verna

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Spring Sandwort, Minuartia verna. Arnside area, Cumbria, end of July 2018.

At the end of July we returned to Arnside in Cumbria and spent a week in the same holiday cottage as last year.

Our visit coincided with a welcome spell of cooler weather with sunny spells and some rain. Although the weather reminded us of last June’s visit, when we saw Bloody Crane’s-bill (Geranium sanguineum), Bog Asphodel (Narthecium ossifragum) and Dark Red Helleborine (Epipactis atrorubens), much of the the vegetation was very different. Following weeks of drought young birch trees on Gait Barrows had brown leaves and on the lower slopes of Arnside Knott, in short turf over limestone rocks, last year’s carpets of flowers had mostly frizzled up.

I say “mostly”, because there was one plant that was still managing to flower: Spring Sandwort, Minuartia verna. It’s a small and rather subtle plant, but its cushions of leaves and pretty white flowers were a welcome contrast to the curled up brown leaves of Rock Rose (Helianthemum nummularium) and other plants.

Spring Sandwort, Minuartia verna, is a member of the Carnation family, the Caryophyllaceae, like Spanish Catchfly (Silene otites) and Corncockle (Agrostemma githago), which I’ve already written about. The genus Minuartia is widely distributed in the northern hemisphere, in Europe, Asia and North America. Estimates of the number of species in the genus varies: the range in Hortipedia is given as 127 to 244 species. The plants are found in inhospitable alpine and arctic environments, in stony places and on rocky ledges, and many can tolerate very low temperatures. Minuartia verna sometimes grows alongside Mossy Saxifrage (Saxifraga hypnoides), which also has cushions of leaves and white flowers, but with a closer look the two species are usually easy to tell apart.

Minuartia verna is a short-lived perennial and in the British Isles it flowers from May to August. It can be found in areas of Carboniferous limestone and in the British Isles it is quite scarce, found mainly in Northern England, but also North Wales (particularly Cwm Idwal and the Great Orme), parts of Northern Ireland, The Burren in Southern Ireland and in a few areas of the Scottish Highlands (see distribution map). There is also a morphologically distinct population of the plant on the Lizard in Cornwall. The plant usually grows below 600 metres (1960 feet) above sea level, although it has been recorded at 875 metres (2800 feet) on Snowdon in North Wales. Outside the British Isles, it grows in limestone areas in many other European countries and has several subspecies. For gardeners, it makes a good alpine plant.

Minuartia is named after Juan Minuart (1693-1768), a Spanish botanist, pharmacist and plant collector and the specific name “verna” means spring. The Irish name is Gaineamhlus earraigh and the Welsh name is Wlyddgwyrdd y mynydd (which I am told means “mountain breeze”, which is rather lovely).

Another English name for Minuartia verna is Leadwort. The plant is tolerant of heavy metals and grows quite happily on spoil heaps (see picture) and around old mine workings, of lead, zinc and copper. Plants like this that can tolerate high levels of heavy metals are known as metallophytes. Some are obligate metallophytes and will only grow in these conditions. Minuartia verna is classed as a facultative metallophyte – it can tolerate heavy metals but will happily grow elsewhere too.

The ability of Minuartia verna to grow in places contaminated with heavy metals has been documented in several scientific papers, including:

 

Viper’s Bugloss, Echium vulgare

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Viper's Bugloss, Echium vulgare

Viper’s Bugloss, Echium vulgare, in the Norfolk Brecks.

I love Viper’s Bugloss, Echium vulgare. It’s a plant that always makes me smile, because of its lovely flowers and because it brings back happy childhood memories. The first time I saw it was as a child of four or five at Newborough Warren on Anglesey, on holiday to visit my Welsh grandmother. It is a plant that normally teems with life and it is always worth checking the flowers for bees and butterflies.

At the end of June we walked from Santon to Brandon in the Brecks (see Note). It was very, very dry and vegetation was crispy underfoot. Ragwort (Senecio jacobaea), Wild Mignonette (Reseda lutea) and Viper’s Bugloss were nearly the only plants in flower. Viper’s Bugloss was proving the most popular plant for insects and almost every flower spike was being visited by bumblebees and Small Skipper butterflies. There were often half a dozen butterflies per plant.

Newborough Warren and Breckland have one thing in common – well drained, sandy soil. In addition, Breckland also has very low rainfall. Viper’s Bugloss, Echium vulgare, is well adapted to these conditions because it has a long tap root that reaches deep into the ground for water.

Echium vulgare is an erect, bristly plant which grows up to 75cm (about 30 inches) tall at maturity. It is a biennial, although it may take three rather than two years to flower. It will normally die after flowering. In its first year or two it forms a basal rosette of hairy, lance-shaped leaves. In its final year it produces dense cylindrical spikes of flowers, usually a main spike surrounded by several smaller ones. The flowers are violet-blue and bell-shaped and continue from early June throughout July and into August.

Echium vulgare is a member of the Borage family, Boraginaceae, and a relative of Green Alkanet, Pentaglottis sempervirens, which I wrote about in April 2017. The Online Atlas of the British and Irish Flora lists the following places where it can be found: bare places on chalk and limestone downs, on heaths, in quarries and chalk-pits, in cultivated and waste land, along railways and roadsides, and by the coast on cliffs, sand dunes and shingle. The plant is native to most of Europe and temperate Asia but it has been introduced into the United States, where it is listed in the Invasive Plant Atlas. It is especially invasive in Montana, Washington and Wyoming and Montana State University has published an online pamphlet describing its biology. As it needs bare soil for the seeds to germinate, its presence can be a symptom of overgrazing.

In the UK, Viper’s Bugloss is a great plant for wildlife and will grow well in gardens if it is sunny and there is bare soil and there are named cultivars such as ‘Blue Bedder‘. Our garden has the right kind of soil but the garden faces north, so although Viper’s Bugloss does well in summer, it can die off if it is in an area of the garden that is in deep shade during winter. On our allotment Viper’s Bugloss does better, as the soil is the same but it is sunny all year round.

The name Viper’s Bugloss (sometimes given a hyphen, Viper’s-bugloss) comes from the plant’s snaky appearance. The flowers’ long red stamens look a bit like snakes’ tongues and the fruits are said to resemble adders’ heads.The stem is speckled, which is suggestive of snake skin. In the United States the plant is often known as Blueweed. A close relative, Echium plantagineum, Purple Viper’s Bugloss, sometimes occurs as an arable weed in the British Isles. It is known in Australia as Paterson’s Curse, having allegedly been introduced in the 1880s by a Jane Paterson as a garden flower. It is now a serious problem in many pastures.

Both Echium vulgare and Echium plantagineum contain toxic pyrrolizidine alkaloids, which can cause liver damage. There are no reports of human poisoning but horses and sheep are at risk and following bushfires in the Canberra area of Australia in 2003, forty horses were put down after eating too much Echium plantagineum. If you’re in the UK, don’t let this put you off growing Viper’s Bugloss. I bought my seeds from Emorsgate Seeds, though there is so much of the plant in some places that I’m sure it would be OK to collect some from the wild.

The bee to the right of the flower is Anthophora bimaculata, the Green-eyed or Little Flower Bee. In Norfolk it is found in the Brecks. When we visited in late June, males (with their characteristic green eyes and mosquito-like high pitched buzz) were patrolling the Viper’s Bugloss flower spikes, on the hunt for females.


Note: Although Brandon is in Suffolk, we stayed on the Norfolk side of the river throughout, and Brandon station is in Norfolk, so we didn’t need our passports.