Isotrema Rafin.
Isotrema is a segregate of Aristolochia. It comprises ca. 50 species from temperate and tropical Asia, North and Central America. Several species, mostly woody climbers, are cultivated as ornamentals.
References
Brady A. & Gorman C. (1989) Aristolochia. In: Walters S.M. & al. (eds.), The European Garden Flora, vol. 3. Cambridge University Press, Cambridge: 417-418.
Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.
Ohi-Toma T., Sugawara T., Murata H., Wanke S., Neinhuis C. & Murata J. (2006) Molecular phylogeny of Aristolochia sensu lato (Aristolochiaceae) based on sequences of rbcL, matK, and phyA genes, with special reference to differentiation of chromosome numbers. Syst. Bot. 31: 481-92.
Pfeifer H.W. (1966) Revision of the north and central American hexandrous species of Aristolochia (Aristolochiaceae). Ann. Missouri Bot. Gard. 53: 115-196.
Wagner S. (2010) Evolution of shrubs and lianas within Aristolochia subgenus Isotrema – combining molecular phylogeny with biomechanical and anatomical approaches (Evolution von Wuchsformen innerhalb der Aristolochia Untergattung Isotrema - Molekulare Phylogenie kombiniert mit biomechanischen und anatomischen Untersuchungen). Dipl. Biol. Thesis, Fakultät Mathematik und Naturwissenschaften, Technischen Universität Dresden, Germany.
Wanke S., González F. & Neinhuis C. (2006) Systematics of pipevines - combining morphological and fast-evolving molecular characters to investigate the relationships within subfamily Aristolochioideae (Aristolochiaceae). International Journal of Plant Sciences 167:1215-1227.
Zu X.-X. & al. (2019) Reinstatement of Isotrema, a new generic delimitation of Aristolochia subgen. Siphisia (Aristolochiaceae). Phytotaxa 401(1): 1–23. [available online at: https://www.researchgate.net/publication/332331515_Reinstatement_of_Isot...