What is (a) Producing umbels. (b) Of or pertaining to a natural order (Umbelliferæ) of plants, of which the parsley, carrot, parsnip, and fennel are well-known examples called?

umbelliferous — (a) Producing umbels. (b) Of or pertaining to a natural order (Umbelliferæ) of plants, of which the parsley, carrot, parsnip, and fennel are well-known examples. (Webster's 1913.)

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