Notes on surveyed areas and willow identification -- Tidmarsh Farms, Plymouth, Sep--Nov 2011 next

During the survey of Tidmarsh Farms in the fall of 2011 we found a few solitary native willows (a single plant of S. eriocephala, two or three S. nigra, including seedling and a few plants of S. discolor). and abundant European Salix cinerea / S. atrocinerea (= S. cinerea ssp.oleifolia). Dots correspond to photographed mature plants, roughly depicting the area of infestation within the Farms. The two areas examined more closely are shown pink on the map: a small portion of an abandoned cranberry plantation in the northern part of the Farms now covered with old willows and a large recently drained pond with old willows on perimeter and abundant seedlings on the bottom (presented in a separate report). The exact identification of each willow proved to be somewhat difficult. Only some mature willows could be decisively identified as S. atrocinerea or S. cinerea. The majority of seedlings and saplings looked like S. atrocinerea, but most of old willows fitted more to S. cinerea by their leaf color, lack of reddish hairs, hairy branchlets and buds. At the same time, many old willows had slender branchlets typical for S. atrocinerea. In Europe these two willows are vicarious, and across most of their ranges do not have an opportunity to hybridize. It is probable that after being introduced to eastern North America, they formed abundant hybrids [IK] The reason for such variability still need to be clarified. Longer version:: Could this variability be attributed to possible hybrids of these two willows (which existence is still debatable), or else to hybridization with native willows remain unclear. It cannot be as well excluded that variability range of S. atrocinerea (and S. cinerea) is higher than XXXXX SDELAT VREZKU

Geotagging implemented by synchronizing camera (photo timestamp) with standalone Garmin GPS, coordinates kept in separate files, exif headers left unmodified. Maps created using online service by GPS Visualizer (http://www.gpsvisualizer.com/)