12. Dipteridaceae
双扇蕨科 shuang shan jue ke
Authors: Zhang Xianchun, Masahiro Kato & Hans P. Nooteboom
Rhizome long creeping, solenostelic or protostelic, covered with bristles or articulate hairs. Stipe with a single vascular bundle proximally and polystelic distally; lamina (sterile ones, at least) cleft into 2 or often more subequal parts; veins highly reticulate, with included veinlets. Sori exindusiate, discrete, compital (at intersection of connecting veins), scattered over surface, or fronds dimorphic and fertile ones covered with sporangia; sporangia maturing simultaneously or maturation mixed, with 4-seriate stalks; annuli almost vertical or slightly oblique; spores ellipsoid and monolete, or tetrahedral and trilete, surface smooth or rugulose, ca. 64 or ca. 128 per sporangium; gametophytes cordate-thalloid. x = 33.
Two genera and ca. 11 species: E and S China, India, C and S Japan, and from SE Asia to Melanesia and W Polynesia; two genera and five species in China.
The Dipteridaceae are a rather primitive group of ferns related to the Gleicheniaceae and distant from the Polypodiaceae, with the fossil record beginning in the Upper Triassic.
Lin Youxing. 2000. Dipteridaceae and Cheiropleuriaceae. In: Lin Youxing, ed., Fl. Reipubl. Popularis Sin. 6(2): 1-6.
