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Word of the Week: Cupule

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

Cupule [KYOO-pyool] (botany noun): A cup-shaped structure of hardened bracts at the base of an acorn. In other words, it is the cap of the acorn!

If you move around High Park this time of year, you will probably notice that much of the forest floor and the sandy soil in the Black Oak Savannah is covered with acorns!

These acorns might differ from each other in size, shape, and colouring but you can expect that their general anatomy will be the same. They come with a stalk, the remains of a style, the nut, and a cupule.

In High Park, we have White Oaks, Red Oaks, Black Oaks, and even some hybrids. Looking at their acorns can be a really helpful way to identify the tree.

Acorns from the red oak tree are 2 to 3 centimetres long and are round in shape. They also have a scaly cupule that covers less than ¼ of the acorn.

Acorns from the white oak tree are 1.2 to 2.5 centimetres long and have an oblong or ovoid shape.The cupule of the acorn has a distinctive bubbly look and covers about ¼ of the acorn.

The acorns of the black oak tree are 1-2 cm long and equally as wide. They also have a slightly hairy cupule that covers about half of the acorn. The nut can also have some dark stripes on it.

Keep and eye out for acorns from the White Oaks, Red Oaks, and Black Oaks of High Park on your next visit!