Suomen Luonto
English summaries 8/2002

Food from fungus forays
by Lasse Kosonen
Pages 4—11

For those wishing to gather food from the forest knowledge is the best tool. One can easily find new species (in the personal awareness sense) from familiar parts of the forest. Moreover, mycological research continually reveals new facts about these organisms.

The first species to excite the collector in spring is the false morel. By midsummer there are more fungi about. The experienced collector is aware of the best spots for Boletus species like the penny bun, and chanterelles. Last spring and summer (2002) were extremely dry over most of Finland, however, resulting in few toadstools of any kind. Autumn rains may still save the late autumn’s crop, though.

A good axiom for the toadstool collector is: Pick only species familiar to you! Unfamiliar kinds can be gathered and identified with the help of a book when one arrives home. But these should always be placed in a separate receptacle as they are picked.

Edible fungi of nutritious value can be roughly divided into two groups: those that have to be boiled before frying and those that can be dropped into the frying pan without further preparation. At least the toxic false morel, and the more bitter-flavoured milkcaps need pre-boiling. Most other edible kinds can be popped straight into the frying pan. In fact many of them deteriorate if accidentally cooked in boiling hot water.

Fungi are generally preserved for winter use by drying or deep-freezing, although the Finns continue to keep them in saline or vinegar. Finns place great value on milkcaps, the chanterelle, the funnel-shaped chanterelle, and the penny bun. With the exception of the penny bun and chanterelle, which are popular everywhere, different species of fungi are regarded as delicious in different countries. The Finns’ taste for milkcaps comes from Russia, the Mecca for consumers of Lactarius fungi.

Some 50-60 species of fungi in Finland are toxic, 20 of these being of importance from the human viewpoint. Despite large amounts of toadstools being collected by Finns, the medical literature records only 327 cases of fungus poisoning over the period 1903-1994, 17 of them fatal. Deadly poisonous species are the destroying angel (Amanita vilosa), the false morel when raw, the blood red cortinarius (Cortinarius orellanoides) and the brown roll-rim (Paxillus involutus). Responsible for more cases of fungus poisoning in the world than any other species, the death cap (Amanita phalloides) is a rarity in Finland, being found only in the Åland islands, the Turku archipelago, and the immediate neighbourhood of Turku. This species has never been responsible for a death in this country.

Every year in Russia dozens, even hundreds, of people die of fungus poisoning. In 1972 alone, in Sweden 45 people were hospitalised after ingesting a destroying angel mushroom. Statistics for 1979-1999 in Sweden reveal 31 cases of poisoning due to the blood red cortinarius. Thanks to their long tradition of toadstool picking, an extensive literature, and fungus advisors, Finns have a good knowledge of fungi in general. Most of the population are mycophiles - people who like eating mushrooms and toadstools.

Secret of palsa mire is a heart of ice
by Tero P. Saari
Pages 18—24

The palsa mires of northern Lapland are a special feature of Finnish nature. Palsa is a mound composed of peat with a frozen heart that never melts, even in summer. Should the mean temperature over a several-year period rise, palsa mounds shrink. If, on the other hand, the temperature falls, they expand.

Palsa mires form most readily in regions with a continental climate, where there is minimal precipitation and where the annual mean temperature is around minus one Celsius. The development of a mound into one of "average proportions", i.e. a few metres in height, takes decades or even centuries. With changes in the climate or local microclimate, the development of palsa mounds also alters: at present they are melting. The width of the mounds vary from a few metres to over hundreds of metres. Their height also radically differs. In general, palsa mounds rise to 1.5 to 2 metres, but in Enontekiö (north-western Finland) the highest examples reach 7 metres. Elsewhere on the globe there are palsa mires that are over ten metres high. Around the mass of virtually solid peat and ice there is an extremely wet moat-like ring which is difficult to get cross.

Palsa mires have a characteristic vegetation. Lichens and crowberry, mixed with cloudberry and dwarf willow, clothe the surface. Sphagnum moss and cotton-grasses populate the wet areas surrounding the mound, with sedges (Carex rostrata, C. rotundata and C. canescens), predominating slightly further away.

Palsa mires are a veritable paradise for birds, harbouring numerous arctic species like the bar-tailed godwit, broad-billed sandpiper, spotted redshank, red-necked phalarope, red-throated pipit and Lapland bunting.

Thistle fields provide an oasis for butterflies
by Kimmo Saarinen
Pages 26—29

Thistles are one of the most typical groups of plants flowering in the late summer and early autumn period. Despite being an annoyance to many people, they are extremely popular with insects. For many butterflies, for instance, the purple inflorescences of thistles hold an irresistible attraction.

Four kinds of thistles are common in Finland, namely the sow thistle, field thistle, spear thistle and marsh thistle. All of these are common and possess purple florets that are highly attractive to butterflies and some moths. The commonest species, the field thistle, is most abundant along road verges, on wasteland, and in fields. It produces numerous inflorescences offering large quantities of nectar. Among the most common guests at this ‘table’ are brimstones, small tortoiseshells, commas and peacocks, all of which hibernate in the adult form. In late summer, field thistles also attract apollos, large grizzled skippers and silver-washed fritillaries (these species having a limited range, however). Among the migrants, the small and green-veined whites, pale clouded yellow, painted lady and red admiral find thistles very much to their liking. As flowering ceases, the field thistle continues to entice peacocks and brown hairstreaks (another rare species).

Although the tall marsh thistle has more inflorescences than the field thistle, these are smaller. It grows in lush, damp meadows and on dry fields, along stream verges, and on lake shores. The thistle is popular with the rather large dark green and high brown fritillaries, as well as the silver-washed fritillary (confined to south-eastern Finland). Dozens of specimens of the silver-washed, our largest fritillary, can sometimes be seen in the south-east on a meadow where marsh thistle is growing in profusion.

The large blossoms of sow thistle are attractive to butterflies as early as July, when this species comes into bloom. One of the most obvious butterfly visitors is the black-veined white. Sow thistle attracts more nocturnal moths than the other thistle species. These include the bedstraw hawk moth and various noctuids.

Aside from butterflies, many beetles, bumble bees, honey bees, hoverflies and small thrips commonly visit thistles to sample their plentiful supply of nectar.

Ice age relic plants
by Seppo Vuokko
Pages 30—35

15,000 years ago all of Finland was covered in ice and lifeless. The climate began to grow warmer and the continental glacier to melt some 14,000 years ago. New ice forming on the old Scandinavian mountain chain flowed east and south, but meanwhile the edge of the ice sheet was melting faster than the glacier could creep forwards. About 13,000 years ago the glacial edge reached Finland. On its southern fringe the Baltic Ice Lake formed with, however, dry land fronting the ice in the south-east and east. The plant cover of the time has not survived anywhere at all in its original form. However, we may make logical conclusions about what kind of flora and fauna existed next to the glacier.

Gradually, the ice retreated further and further away, the land began to uplift due to isostasis, and the climate warmed. Shrubs and trees conquered the land, driving the pioneer species before them. As forests spread, numerous tundra and steppe species vanished without trace - in addition to plants, countless fungi, insects, birds and mammals disappeared. Not all of them, though. A few remained on fells, despite the climate there being more moist than it had been during the Ice Age and the prevailing conditions more severe. Steppe plants, on the other hand, remained entrenched in the drier central parts of the continents.

Some plants found sanctuary in the ‘sea of forest’ now clothing the land. Fragments - relics - of steppe plants have remained to this day on the warmer, south facing, sunbathed sides of rocky canyons and eskers. Repeated forest fires have kept soil acidity in check in such locations. The steppe plants include wild thyme, pasque flowers and yellow oxytropis.

On bare rock cliffs facing north and east, where cold conditions prevail and water trickles down the surface during the warm part of the year, a few tundra species were able to come to terms with the environment. Such late glacial relics have survived here and there, with their main stronghold in Kuusamo, part of the south-eastern Lapland region. This is due to the area’s calcium-rich rocks and deep, vertical sided canyons. Tundra species now found in these locations include the net-leaved willow, yellow mountain saxifrage, mountain avens, alpine butterwort and arnica.

Teksti: Leigh Plester