Manitoba Maple - Acer negundo - Érable negundo

So the most recent tree to go into full bloom here in Montreal is Acer negundo (Manitoba maple). The long, pendulous male flowers are quite eye-catching at the moment.

Acer negundo staminate inflorescences

Like Acer saccharinum, A. negundo is wind-pollinated. Unlike A. saccharinum, A. negundo is dioecious [1,2,3], which means that each tree is either male or female. As with A. saccharinum (and other wind-pollinated species), the flowers are not perfumed or showy, as there is no point in investing energy in characteristics which are used exclusively to attract pollinators. Instead, wind-pollinated plants invest energy in producing a huge amount of pollen to make up for the tremendous inaccuracy of wind-pollination.

Acer negundo staminate inflorescence

A. negundo is introduced in this region, being native to places in the U.S. and in central Canada [native range map here]. This tree is a popular choice for landscaping, and because of this has been spread globally. This species takes very well to disturbed habitats and so has a tendency to spread in human-occupied land. A. negundo also prospers in riparian areas (transition zone from land to river). The species spreads easily and is naturalized in southern Quebec, New Brunswick, Nova Scotia, PEI, and various parts of the United States [3].

A. negundo staminate inflorescence

There is some variation in the timing of emergence of flowers and leaves in A. negundo, depending on geographical (climate) factors [3]. In some places, the flowers appear first, and then the flowers. As can be seen in the photos I have, at least here in Montreal, the flowers and leaves appear simultaneously; this is likely related to the shorter growing season here compared to more balmy southern climes.

A. negundo staminate inflorescence

Unlike most maples, A. negundo has distinctive compound leaves. Image of leaves here.