During a recent greenhouse visit a species of Ephedra was in "flower". Ephedra is a small shrubby plant of cool deserts better known as the source of ephedrine, and in Asia it's long been an herbal remedy for asthma and poor circulation. Here's several of the pollen producing cones. Branching structures that bear the sporangia and protrude out from among bracts that compose the little cones. The bracts occur in pairs and subtend the sporangia bearing axes each of which during development is enveloped by a fused pair of smaller bracts. So here's a pollen producing structure surrounded by a pair of modified leaves growing in the axil of a bract. That's pretty flower-like even down to having a perianth. Ephedra even has double fertilization, but both produce zygotes, although only one will develop, so no endosperm is formed. The genus is a member of the gnetophytes, a group of pretty strange plants that was once thought to have affinities to flowering plants.