Babiana ringens, a South African flowering plant locally known as the Rat's Tail, shows a very particular evolution to invite pollinating birds to dip their beaks into its flowers: a specialized bird perch. B. ringens's flowers grow on the ground, which could mean it garners less attention from birds that don't wish to hang around in that dangerous spot for too long. To entice the Malachite sunbird, the plant has evolved to grow a firm stalk in a perfect perching position for feeding.
This one is interesting because the very same plant shows a distinct difference depending on where it is, according to University of Toronto researchers--when it relies on the sunbird for pollination, it grows a long and appealing stalk (quiet, guys), while in areas with lots of potential pollinators, that stalk has shrunk over many generations of less use. But the stalk is still a major advantage for the plant--plants without the stalk, whether it was broken off or whatever, produce only half as many seeds as those with an intact stalk.