Edible spring fungi in southern taiga communities

Morphological characteristics of fruit bodies of several species of edible spring fungi were studied in southern taiga plant communities of Kirov region, European part of Russia. Investigation revealed productivity of Gyromitra esculenta Pers. Ex Fr. (9.7 kg/ha), Gyromitra gigas (Krombh.) Cooke (8.0 kg/ha), Verpa bohemica (Krombh.) J. Schröt. (4.8 kg/ha), Morchella esculenta (L.) Pers. (0.7 kg/ha). Connections between morphological parameters of fruit bodies and weight were defined for each species.


Introduction
Kirov region is considered one of the most fungi-rich areas of European part of Russia [1,2]. Studies on productivity and stocks of fungi [3,4,5], peculiarities of their use [6,7] and species identification [8,9,10] are traditionally conducted in the region. However data on biology of edible spring fungi is limited [11].
First spring fungi in Kirov region belong to order Ascomycota, or sac fungi, class Pezizomycetes, most of which have macroscopic fruit bodies of various forms and colors [12] False morel (Gyromitra esculenta Pers. Ex Fr.) is one of the first spring sac fungi in Kirov region, it starts fruiting right after the loss of snow cover and continues till the end of May [13]. During certain years it can last till June, 20. The species is found on sandy, bare or low-matted soils, on openings, fire sites, along the roads, in coniferous (predominantly pine) or mixed forests [14].
Fruit body (sporocarp) is brittle and delicate, with cerebriform cap on short stipe, filled with septums and convolutions. Chocolate-brown cap can reach up to 120 mm in diameter, stipe-to 60 mm high [14,15,16].
Besides G. esculenta one more Gyromitra species is found in forests of Kirov regionsnow false morel (Gyromitra gigas (Krombh.) Cooke). Visually these two species are alike, but snow false morel's apothecium is light sienna-yellow, roundish or oviform, plicate, it intergrows with white short stipe. The fruit body can reach 300 mm in diameter [17]. It is usually found in groups on rich soils, rarely solitary; in deciduous and mixed forests, often in birch forests [18]. Fruit bodies appear from the middle of April till the end of May.
False morel and snow false morel (G. esculenta and G. gigas) are considered conditionally edible species; some researchers define them as poisonous due to the presence of gyromitrin toxin infruit bodies [19]. Concentration of the toxin is unstable and varies from almost harmless to deadly doses [20], it is significantly lower in G. gigas, compared to G. esculenta. According to numerous studies right preparation of raw material (30-minutes long boiling of fruit bodies or 1-month long drying) can reduce the level of toxin or totally neutralize it [21,22]. According to official data, cases of G. esculenta poisoning in Kirov region are mostly caused by improper preparation of fruit bodies or by consumption  [17]. In folk medicine tincture of G.gigas fruit bodies is used to treat joints and lumbus radiculitis [6]. In 1970-80's dried false morels were the objects of organized collection. InKirovregionthespeciespreserveditseconomicvalue.
Early morel (Verpa bohemica (Krombh.) J. Schröt.) is another rather popular spring fungi, has brown crinkly cap 20-30 mm in diameter on white-cream stipe 40-140 mm high and 15-20 mm in diameter [23]. It prefers humus-rich soils in coniferous-deciduous forests of green-moss type. Usually found in sparse tree stands under aspen and linden [24]. Fruiting of V. bohemica is relatively short and starts in the second decade of May. But depending on weather conditions it can shift to the end of May, and end in the beginning of June [13]. The species is also conditionally edible, of 3 rd category. It is used in folk medicine to treat eye disorders and digestive tract [6,8].
Morel (Morchella esculenta) is collected throughout its range and is a subject of industrial collection in many areas [25,26] 2. False morel False morel (Gyromitra esculenta Pers. Ex Fr.) within the studied area typically inhabits spruce-pine and pine cowberry-green moss forests with birch. Fruit bodies occurred on sandy soils. Most fruit bodies of G. esculenta were found along forest roads and on damaged soil cover, where clusters of fruit bodies were the largest.
False morel average fruit body weight was 29.0±2.3 g, varying from 1 to 152 g. Variability level of the parameter was very high (CV=97%), significantly higher than for other parameters. Observations showed that fruit body weight was higher in pine green moss, spruce-pine bilberry-green moss forests and on the opening under spruce forest, compared to other studied plant communities (figure 1).
Productivity of fruit bodies was 9.7 kg/ha.

Figure 2. Distribution of
Gyromitra esculentafruit bodies by weight, height and cap diameter.

Morels
Morels were found in scanty groups mostly in spruce-birch herbaceous (littery), pine lingonberry-green moss and pine calamagrostis plant communities within the spots of disturbed soil cover.
M. esculenta productivity inn studied habitats was 0.7 kg/ha. Some researchers note the productivity of morels in old herbaceous aspen forest being 3.9 kg/ha [27].

Conclusion
The study revealed average values of morphometric parameters of main economically important spring sac fungi. All studied features were highly variable, sporocarp weight being the least stable. Correlations between fruit body weight and morphometry were defined for each species. It was determined that power function is reliable for correlation approximation of sporocarp weight and its morphometric peculiarities. Productivity of spring fungi in southern taiga communities in Kirov region reached 9.7 kg/ha for Gyromitra esculenta, 8kg/ha -for Gyromitra gigas, 4.8 kg/ha -for Verpa bohemica,and 0.7 kg/hafor Morchella esculenta.