What's the difference between brumal and hiemal?

Brumal

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Definition:

• (a.) Of or pertaining to winter.

Example Sentences:

Hiemal

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Definition:

Example Sentences:

• (1) Chloroform extracts of Equisetum fluviatile, E. hiemale var.
• (2) It was found that the most active plant was E. hiemale var.