"bearing cones," also, later, "belonging to the order Coniferae," 1660s; see conifer + -ous.
Entries linking to coniferous
conifer n.
"a plant producing cones, a plant of the order Coniferae" (which includes pine, fir, and cypress trees), 1847, from Latin conifer "cone-bearing, bearing conical fruit," from conus "cone" (see cone) + ferre "to bear, carry" (from PIE root *bher- (1) "to carry").
-ous
word-forming element making adjectives from nouns, meaning "having, full of, having to do with, doing, inclined to," from Old French -ous, -eux, from Latin -osus (compare -ose (1)). In chemistry, "having a lower valence than forms expressed in -ic."