What flower is कठगुलाब?

The plant is a perennial high-climbing vine that rankly overtops bushes below it, bearing yellow flowers, surprisingly large, teardrop-shaped fruiting capsules, and large, palmately lobed leaves.

 One expects a vine like that to be one of the many species of the Morning-Glory Family coloring our landscape right now, and the flowers' basic structure confirm that it really is a morning-glory. However, those oversized fruits next to the smallish flowers (2-1/3 inches or 6 cm across), and the deeply lobed leaves don't seem right. And not many morning-glory blossoms are yellow. Most morning-glory-type vines are members of the genus Ipomoea, so the traits of that genus are associated with the whole Morning-Glory Family – the Convolvulaceae. But, this is not Ipomoea – it’s Merremia tuberosa, a whole other genus.

Merremia tuberosa is native to Mexico and Central America, but is grown as a garden ornamental throughout the world's tropics. It's escaped into the wild so often that it's considered a pantropical weed. Occurring so widely, it goes under many names. Some of the English ones are Woodrose, Spanish Arborvine, Hawaiian Wood-rose, Spanish Woodbine and Yellow Morning-glory. Of course those aren't roses, in fact they aren't any kind of flower, but rather they're a vine's thin-walled, capsular fruits subtended by much enlarged, dried-out, stiff, irregularly incised sepals.

Inside each egg-size capsule, four black, fuzzy seeds are suspended not touching the capsule's walls, as shown below: Three ¾-inch (18mm), black, fuzzy seeds are shown below: Why would a fruiting body evolve to look like a brown, woody rose? Its similarity to a wooden rose is incidental. Maybe the large, stiff sepals catch wind, causing the capsule to flap about on its slender stem, slinging seeds here and there. Maybe the seeds' hairs simply expose more surface area to the wind, helping the seeds sail farther. The "wooden flowers" remain pretty for weeks.

Thanks to: Jim Conrad's Naturalist Newsletter