Dicranopteris linearis var. linearis
Content
Distribution
Asia present, Australasia present, Malaysia present, Polynesia present, tropical and subtropical Africa present
Tropical and subtropical Africa, Asia, Malaysia, Australasia, and Polynesia.
Notes
Polypodium dichotomum Thunb. was described from Japan, and as noted by Nakai (l.c.) is not quite identical with Polypodium lineare Burm. (Burman's specimens, preserved at Geneva, are from Ceylon). I have therefore ranked it as a Dicranopteris linearis var. dichotoma (). The lamina of the fronds is thinner than in var. linearis and the veins are prominent on the upper surface. This may be connected with the fact that (at least in part of its range) the fronds of var. dichotoma only last for one season, dying in the winter, whereas those of var. linearis grow for an indefinite period which is usually not climatically limited. Var. dichotoma apparently occurs also in China and probably in the Sikkim region; field studies in these regions are needed to establish clear distinctions between var. linearis and var. dichotoma.