 As with other ferns , the leaves develop in a circinate pattern . They begin as small , tight spirals which unroll as the leaf matures . At full maturity they are held erect with the leaflets unfolded , except in Pilularia whose leaves have no blade . Temperate species are deciduous , losing their vegetative leaves in winter . Tropical species may also lose their leaves during the dry season . These leaves are photosynthetic , and produce most of the food used by the plant . 
