Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Solanales
Family: Solanaceae
Subfamily: Solanoideae
Tribe: Solaneae
Genus: Solanum
Species: S. wendlandii
Binomial name: Solanum wendlandii
Common name: Giant Potato Vine, Giant Potato Creeper, Costa Rica Nightshade, Blue Potato vine, Giant Potato creeper, Paradise flower, Divorce Vine

 All parts of the plant are highly toxic if ingested due to Solanine and other alkaloids.

Solanum wendlandii is a semi-evergreen large vigorous vine from Southern Mexico, Costa Rica, Guatemala and north-Western South America. Costa Rica that can grow to 10 to 15 feet tall and wide. It has large ovate 10 to 20 cm long ovate thick leaves that are 4–8 cm wide. The leaves undersides often have hooked prickles scattered along the midrib. During the whole of summer large terminal panicles of >5 cm wide deep purple flowers are produced, these fade to lavender, then white over their long blooming period.
After flowering ovoid berries which are dark green develop, these turn to red on maturity.
It a reasonably rare plant which is grown in some New Zealand garden.

Photos are of plant growing in the Tupare public gardens, New Plymouth, Taranaki.
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Some of the leaves have a few thorns on the main rib on the underside.
 

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/