Of, relating to, or resembling plants of the dogbane family; apocynaceous.
From Apocynum with the adjective suffix -eous (variant of -ous), used interchangeably with apocynaceous to describe members of this plant family.
Apocyneous is basically the old-fashioned way to say apocynaceous—botanists updated the terminology, but both names survive in older plant books!
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