Acer nigrum – Black Maple

Black Maple near Oxford Mills

Full-sized shade-tolerant tree, closely related to Sugar Maple.  In eastern Ontario, uncommon but widespread and can be locally abundant especially on favoured habitat of low rich soil of floodplains, often wetter than preferred/tolerated by Sugar Maple.  Sometimes found on drier uplands and appears to do better along roadsides and in urban areas than Sugar Maple. 

Black Maple leaf (large) vs. Sugar Maple leaf

Leaves are generally large and with thick leathery texture, often less sharply lobed than Sugar Maple, tending to curve downwards at margins, with downy hairs on leaf undersides and along petiole, petioles long and often with stipules at base.  Compared to Sugar Maple, twigs thicker, buds often blunter, lenticels more prominent.  Bark often scalier or more corrugated than Sugar Maple. 

 
Good sites to find this species in eastern Ontario include: Reveler Conservation Area, Summerstown Forest, Blom Property, Oxford Mills, Almonte, and Fitzroy Provincial Park (at the Pine Grove Campground near the washrooms by camp sites 87 to 91).
 
Selected photographs with location coordinates in iNaturalist:
 
http://www.inaturalist.org/observations/5186998 (comparing leaf to Sugar Maple leaves, Reveler CA near Crysler)
http://www.inaturalist.org/observations/2781996 (roadside tree, Reveler CA near Crysler)
http://www.inaturalist.org/observations/2712216 (sapling in shade, Summerstown Forest near Cornwall)
http://www.inaturalist.org/observations/4986081 (leaves and twigs, Blom Property near Mountain)
http://www.inaturalist.org/observations/4984648 (leaves and twigs, Blom Property near Mountain)
http://www.inaturalist.org/observations/4985141 (mature tree, Blom Property near Mountain)
http://www.inaturalist.org/observations/4986341 (mature tree, Blom Property near Mountain)
http://www.inaturalist.org/observations/5140983 (sapling at Macoun Marsh, Ottawa)
http://www.inaturalist.org/observations/2509416 (roadside tree, Experimental Farm, Ottawa)
http://www.inaturalist.org/observations/4970064 (mature tree, Gemmill Park, Almonte)
http://www.inaturalist.org/observations/4941423 (leaves, petioles, stipules, Gemmill Park, Almonte)
 
Acer nigrum entries in iNaturalist: