P. sect. Camptogynium
K. Krause, Engl., Das Pflanzenreich IV.
23Db (Heft 60): 3, 127. 1913.
Type species: P. longistylum K. Krause
In contrast to P. jacquinii which has setose stems and thin cordate blades with prominent veins, P. longistilum (P. sect. Camptogynium) has glabrous stems, oblanceolate, subcoriaceous blades with obscure primary lateral veins. The chief reason for its unique status as the only member of a section is the peculiar prolonged style which is deflected to one side and has a cupular apex. It is perhaps not so unique as Krause assumed. Other species are now known to have prolonged styles which are deflected to one side, among them are two undescribed species with cordate blades from western Ecuador, P. acutipistila sp. nov. (based on Croat 731452 and P. sparreorum sp. nov. (based on Jaramillo et al. 25449). However, neither has a cupular apex. These perhaps represent another section or more likely Krause's P. sect. Camptogynium may have to be incorporated in P. sect. Calostigma where it might be easily accommodated.