CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) is an international agreement between governments. Its aim is to ensure that international trade in specimens of wild animals and plants does not threaten their survival. Roughly 5,000 species of animals and 25,000 species of plants are protected by CITES. They are all listed in the Cites Appendices. For information re wild collecting see here. CITES is concerned ONLY with movement between countries across borders & not movements within countries. Listed Fauna & Flora can be moved across borders but all movements must be licenced. To date a few Passifloraceae such as Adenia fruticosa are listed but surprisingly NO Passiflora species are included in the CITES Appendices.
Depending which Appendix species are listed in, either export licences, or export & import licences are required. Obviously being caught by Customs trying to export a listed species is a serious criminal offence & if a nursery is selling a species which needed an import licence but doesn't have one its also in trouble. It is important to note that even if it gives the species away rather than sells it it is still breaking the law. It is worth reading the small print of CITES as it recognises the need for specimens of rare species to be removed from the wild if they are endangered. It distinguishes very clearly between removal for scientific study & propagation for non-commercial purposes, to ensure survival of the species, & the destructive removal of plants & or fruit for large scale commercial propagation. As with archeologist & grave robber the lines can however become blurred .
UNEP United Nations Environment Programme. This comprehensive site includes listings of protected areas within countries such as National Parks & The Red List. To access the list enter 'Passiflora' into Red List Search. Some of the Red List species MAY be protected in their country of origin from deliberate picking, collecting, cutting, uprooting, possession and sale BUT possession, propagation or sale in another country is not an offence unless it is also protected by that country's laws. Note that rare listed plants are not necessarily protected by law even in their native country.