Delta maidenhair fern

Description

Adiantum raddianum, the Delta maidenhair fern, is one of the most popular ferns to grow indoors. It is native to South America and its common name comes from its shiny, dark leafstalks that resemble human hair. It typically grows about 17–19 in (43–48 cm) tall and up to 22 in (56 cm) wide. In the wild, it is found on forest floors, rock crevices, river banks, coastal cliffs, and basalt banks along trails and streams. The triangular fronds are semi-erect in the beginning then droop gracefully as they age and can be up to 12 inches (30 cm)long by 6 inches (15 cm) wide. The genus name Adiantum comes from the Greek word "adiantos", meaning "unwetted" (in reference to the leaves). This plant is hardy down to 5 °C (41 °F), so must be grown indoors in temperate regions. However it may be placed outside in a sheltered spot during the summer months.It requires high humidity, well-drained soil, bright indirect light, and a fairly constant temperature. It prefers neutral or slightly alkaline soil and is suitable for USDA hardiness zones 10 and 11. It can be susceptible to scale and mealybug.The cultivars ‘Brilliantelse’ and ‘Kensington Gem’ have won the Royal Horticultural Society's Award of Garden Merit. A. raddianum is sometimes considered invasive in Hawaii and French Polynesia. Adiantum, the maidenhair fern, is a genus of about 250 species of ferns in the subfamily Vittarioideae of the family Pteridaceae, though some researchers place it in its own family, Adiantaceae. The genus name comes from Greek, meaning "unwetted", referring to the fronds' ability to shed water without becoming wet. They are distinctive in appearance, with dark, often black stipes and rachises, and bright green, often delicately cut leaf tissue. The sori are borne submarginally, and are covered by reflexed flaps of leaf tissue which resemble indusia. Dimorphism between sterile and fertile fronds is generally subtle. They generally prefer humus-rich, moist, well-drained sites, ranging from bottomland soils to vertical rock walls. Many species are especially known for growing on rock walls around waterfalls and water seepage areas. The highest species diversity is in the Andes. Fairly high diversity also occurs in eastern Asia, with nearly 40 species in China.