The systematic position of the East Malesian genus Hollrungia K. Sch. within the Passifloracae

In 1888 K. Schumann described a new, monotypic genus of the Passifloraceae from Papua, Hollrungia aurantioides K. Sch. (Bot. Jahrb. 9: 212). Its generic distinction was largely ascribed to the peculiar sessile, cap-shaped, undivided stigma (“tellerformige Narbe”) and a 3-angular ovary. Harms, who elaborated Passifloraceae for the first and second editions of the “Pflanzenfamilien”, provided a figure of a section of the flower and a cross-section of the ovary (1.c. 3, 6a: 86, fig. 25 E-F. 1893, and 21: 495, fig. 218 E-F. 1925), maintaining Schumann’s observation that Hollrungia possesses an androgynophore which brings it alongside Passiflora, but differing from that genus by the undivided cap-shaped stigma. This kind of stigma is rare in the Passifloraceae and Harms recorded it in the family only for two other, monotypic African genera Crossostemma and Schlechterina.