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Word of the Week: Reniform

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Welcome to Word of the Week! Stay tuned for a new word each Friday to amp up your nature vocabulary!

Reniform [REN-uh-fawrm] (adjective): Describing something that is kidney-shaped

This fun word comes from the Latin words “Ren” meaning kidney, and “forma” meaning shape.

Even in the winter, the reniform leaves of Garlic Mustard can easily be spotted on the forest floor of High Park (assuming there is no snow cover, of course).

Garlic mustard is a plant that was introduced to North American in the early 1800s. It is biennial, which means that it sprouts and grows vegetation in its first year, then returns from overwintered roots the following spring to produce seeds.

Garlic mustard is not a very challenging plant to identify once you’ve developed an eye for it, but the variation in size and shape of their leaves can lead to some uncertainty when you’re still learning.

Garlic mustard has two distinct life stages over its first two years, with the leaves looking very different at each stage. In the first year, garlic mustard has reniform leaves that grow in a cluster close to the ground and remain green for the whole year. In the second year, garlic mustard will grow up to 1.2 meters high and will have triangular, alternate, sharply toothed leaves and white flowers. The garlic odor of the leaves will also be stronger in the plant’s second year.

Garlic mustard is more easily identified in its second year but, whether they’re in their first year or second year, you can always look for that deep, distinct shade of green and the pronounced venation of the leaves.

On your next winter visits to High Park, keep an eye out for Garlic mustard and their reniform leaves on the forest floor!