. 2015. Willows (Salix spp.) as pollen and nectar sources for sustaining fruit and berry pollinating insects. Can. J. Plant Sci. 95: 505Á516. Willows (Salix spp.) are ubiquitous in the northern hemisphere, serving as an important pollen and nectar resource for insect pollinators and for the enhancement of insect-pollinated agricultural crops such as fruits and berries. We used a common-garden field test containing seven native North American willow species to assess attractiveness of male and female flower catkins by documenting visits of Andrena spp. (Apoidea: Anthophila), other wild bees (all native), and flower flies (Syrphidae). Most willows in Canada's Maritimes begin flowering very early in spring, as the first wild pollinators become active following winter, and stop flowering by mid-May. A later-flowering group normally begins flowering in mid-May and stops flowering by mid-June. Pollinator species were largely opportunistic, visiting whatever species of willow flowers were available during foraging, but Andrena dunningi appeared to prefer flowers of S. nigra and S. interior. There was a general preference for male flower catkins, with 72% of Andrena spp. and 82% of all flower flies collecting pollen and/or nectar from male flowers, because pollen is the major component of nest provisioning for most solitary bees and the major source of protein used to develop reproductive tissues in most flower flies. Most andrenids and flower flies were collected within the AprilÁJune flowering period of six of the seven willow species studied, indicating that these willows could be used to support the pollinator community before the flowering period of commercially valuable flower-pollinated crops such as lowbush blueberry, cranberry, and apple.Key words: Andrena, crop pollination, flower flies, Salix spp., wild insect pollinators, willow flowering phenology Ostaff, D. P., Mosseler, A., Johns, R. C., Javorek, S., Klymko, J. et Ascher, J. S. 2015. Le saule (Salix spp.), source de pollen et de nectar pour les insectes qui fe´condent les espe`ces fruitie`res. Can. J. Plant Sci. 95: 505Á516. Le saule (Salix spp.) pousse partout dans l'he´misphe`re nord. Il constitue donc une importante source de pollen et de nectar pour les insectes pollinisateurs et concourt a`l'ame´lioration des cultures fe´conde´es par les insectes, notamment celles qui produisent des fruits. Les auteurs ont recouru a`une parcelle expe´rimentale ame´nage´e en jardin re´unissant sept espe`ces de saule indige`nes al 'Ame´rique du Nord pour e´valuer l'attrait des chatons de fleurs maˆles et femelles pour Andrena spp. (Apoidea : Anthophila), d'autres abeilles sauvages (toutes indige`nes) et des mouches a`fleurs (Syrphidae) en fonction du nombre de visites recense´es. Dans les provinces maritimes du Canada, la plupart des saules fleurissent tre`s toˆt au printemps, lorsque les insectes sauvages pollinisateurs commencent a`s'activer au sortir de l'hiver. Leur floraison prend fin a`la mi-mai. Un groupe plus tardif commence habituellement a`fleurir a`la mi-mai...

responses of two North American willows in acidic clay soils on coal mine overburden. Can. J. Plant Sci. 94: 1269Á1279. Acid-generating mine spoils with low pH are a major problem for revegetation and site reclamation. We compared growth responses of 15 genotypes from two widespread willow species, Salix discolor Muhl. (DIS) and S. eriocephala Michx. (ERI), native to eastern and central North America on two adjacent coal mine spoil sites that differed strongly in both pH (3.6 vs. 6.8) and soil texture. Despite significantly poorer growth responses for several coppice biomass traits on a highly acidic clay deposit compared with adjacent shale overburden, these willow clones demonstrated a surprising tolerance for extremely acidic soil conditions. Analysis of survival and growth uncovered genotype )environment interactions, indicating that both species and genotypic differences within species could be used to select better-adapted genotypes for extreme conditions. Most ERI and DIS clones grew comparatively better on the shale overburden site, but two of eight ERI clones and one of seven DIS clones grew significantly better on the acidic clay site, indicating the possibility for clonal selection for specific site adaptations within a species. Allometric relationships between coppice height and basal stem diameter were constant at both the species and site levels. However, there was a divergence of height and diameter in their relationship with green mass yields on the two different site types.