The sections of the light spectrum which the âredâ and âgreenâ cones perceive overlap and this is why red and green colour vision deficiencies are often known as red/green colour blindness and why people with red and green deficiencies see the world in a similar way.
Wood fern (Dryopteris) Plant these delicate, medium-sized ferns in mixed borders to show off their feathery fronds. Autumn ferns (D. erythrosora) are one of the few ferns with seasonal color variation and their fronds change from pale gold and pink in spring to green in summer and rusty copper in fall. The ferns spread by underground stems to form swaths in garden beds.
More than 20,000 known species of ferns grow around the world. Many types of ferns flourish both outdoors and as houseplants. Outdoor ferns thrive best in partially shaded areas and those grown indoors flourish in bright light, provided they are not placed in the path of direct sunlight.