Comment from Flora of Pakistan: Jacquemontia pentanthos and Jacquemontia paniculata appear to be vicarious equivalents, the former from Asia and the latter from the Americas. They can be difficult to separate on herbarium specimens. Normally the sepals of Jacquemontia pentanthos are only 2-4 mm wide wheras those of Jacquemontia paniculata are 5-6 mm wide. Also corollas of Jacquemontia pentanthos are 2 cm long, wh ile those of Jacquemontia paniculata are not more 1 cm long.
Jacquemontia pentanthos is often shown as Jacquemontiapentantha, including in the Flora of Pakistan. The species was first recognized by Choisy who gave it the epithet pentanthos, basing it on the Greek form of the word. When Don transferred the species from Convolvulus to Jacquemontia, he Latinized the epithet to "pentantha", a change that some considered acceptable, some did not. At the International Botanical Congress in 2017, a proposal to forbid such changes was approved which is why the correct form of the name is nw Jacquemontia pentanthos. [I thank Dr. K. Gandhi for answering my question about the change in the epithet].