‘Beauty bush’ and ‘twin flower’ are common names attributed to two well-recognizable species belonging to the genus Linnaea (16 spp.) – L. amabilis and L. borealis – long admired by botanists and gardeners for their perfumed paired bell-shaped flowers. In the present study, we investigated their floral scent compositions through gas chromatography - mass spectrometry (GC-MS) analysis of dynamic headspace samples. Because the flowers of L. borealis in wild populations are fragrant both during the day and in the evening, circadian variation of scent emission was also assessed for this species. In total, 26 chemical compounds comprise the floral scent bouquets of L. amabilis and L. borealis, identified as monoterpenes (14), benzenoids and phenylpropanoids (5), aliphatics (3), sesquiterpenes (3) and irregular terpenes (1). Whereas monoterpenes, notably (-)-α- and β-pinene, dominated the scent of L. amabilis (over 82% relative abundance), benzene derivates: 1,4 dimethoxybenzene, anisaldehyde, 2-phenylethanol, benzaldehyde and nicotinaldehyde were exclusive to analysed headspace samples of L. borealis, accounting from 52% up to 100% of their relative compositions, in three Swedish populations. A southwestern Finnish population, was characterized by the four first mentioned benzenoid compounds and large amounts of (-)-α- and β-pinenes plus two aliphatic substances. The scent compounds identified for both species are ubiquitous and may serve as generalist attractants/stimulants for a broad assortment of anthophilous insects. The basic work on the flower scent of L. amabilis and L. borealis should inspire studies of their pollination biology, primarily the behaviour-guiding roles of the characteristic emitted volatiles.This article is protected by copyright. All rights reserved.

The ericoid shrub Vaccinium myrtillus is one of several deciduous boreal plants that respond to larval defoliation by compensatory production of a new set of leaves within the same growing season soon after defoliation. This new set is termed as ?secondary leaves?. The physiological performance and longevity of secondary leaves is poorly understood. Following a multi-year larval outbreak in boreal Norway, we therefore monitored the fate of the secondary leaves from 2014 to 2016. We observed that secondary leaves were still green upon onset of snow season and that the same leaves were still attached and green when snow melted in spring. During the early growing season of 2015, the overwintering leaves were consumed by moth larvae, but the secondary leaves produced in mid-July 2015 overwintered and were not consumed by larvae the next growing season. Our monitoring shows that most of these leaves remained attached until late August, while the contents of chlorophyll and nitrogen remained high until July. The flavonoid (anthocyanin) content of overwintering leaves increased shortly after snowmelt, and this coincided with a short-lasting colour change from green to violet-bronze. This was probably a protective response to the abrupt increase in solar radiation. Overall, secondary, overwintering leaves were free of snow and physiologically active for ca 6.5 months, which is 2?3 months more than the longevity of primary leaves in the study area. We conclude that wintergreen leaves probably rendered an important carbon sequestration contribution in the critical first phase of the growing season until new side branches with new leaves were developed. Hence, the novel results reported here on the facultative wintergreen growth habit of V. myrtillus appears to be a successful strategy.

The silica-scaled chrysophyte flora of Swedish Lapland (near Abisko) was examined. Chrysophyte scales were found in 18 of the 32 investigated water bodies (lakes and pools). Altogether, 28 taxa from the classes Chrysophyceae and Synurophyceae were found. The most abundant species was Synura echinulata. Three species were observed for the first time in Sweden: Mallomonas maculata, M. rasilis and Spiniferomonas serrata.