The word cactus may conjure up images of southwestern desert landscapes, but many might be surprised to learn that you can actually find two species of these desert plants living right here in Ontario.

As Canada's warmest and southernmost region, southern Ontario's continental climate is just barely hospitable enough to support cacti in limited areas — and I mean very limited areas.

The eastern prickly pear cactus (Opuntia cespitosa) is definitely the more abundant of the two species present in the province. That being said, it is still considered at severe risk of extirpation and is currently listed as endangered by the Ontario government.

Not that you're likely to see one in the wild, but the perennial succulent cactus is distinguished by its jointed, rounded but flattened green stems, and segmented pads covered in painful barbs. The species can grow up to half a metre in height.

When flowering, the plant boasts yellow, waxy flowers measuring two to three centimetres in diameter.

They grow in dry, sandy areas with plenty of sunshine, often within sandy openings on forested hillsides and in dunes near beaches.

Within Canada, the eastern prickly pear cactus is found only in southern Ontario, and grows in only two known locations on sand spits along the shores of Lake Erie.

According to the provincial government, the species is believed to have once been more widespread in areas near Lake Erie and Lake St. Clair.

Province of Ontario

While it is never a good idea to get too close to an endangered species, the eastern prickly pear bears juicy, edible fruits ripening to reddish-brown. Often grown in gardens and areas where the species is not endangered, the plant's fruit is not particularly prized for its flavour, described as comparable to strawberries, but not as good.

Despite its limited distribution, the eastern prickly pear is actually not as rare as the other species of cactus residing in Ontario.

An even rarer cactus in the region, Opuntia fragilis, known by the common names brittle prickly pear and little prickly pear, is native to much of the west, but is perhaps one of the rarest species in Ontario.

Its known population in the province exists as a lone isolated patch — possibly genetically unique from its closest neighbouring populations more than 1,000 kilometres away.

Located on a remote rocky outcrop in eastern Ontario, this small Opuntia fragilis presence is known as the "Kaladar population," after the small rural community it is located near.