Nephrolepis exaltata, the sword fern, is a species of fern in the family Lomariopsidaceae (sometimes treated in the families Davalliaceae or Oleandraceae, or in its own family, Nephrolepidaceae), native to tropical regions throughout the world. The fronds of Nephrolepis exaltata are 50–250 cm long and 6–15 cm broad, with alternate pinnae (the small “leaflets” on either side of the midrib), each pinna being 2–8 cm long. The pinnae are generally deltoid, as seen in the picture to the right. The pinnate vein pattern is also visible on these highly compound leaves. The edges appear slightly serrate.
Nephrolepis exaltata is a very popular house plant, often grown in hanging baskets or similar conditions. Although the fern may appear totally dead due to frost, it will re-emerge in the spring. In general, the Boston fern likes damp, but not soggy soil that is rich in nutrients. Of the common cultivated ferns, the Boston fern is the most tolerant to drought. The fern thrives best in humid conditions, so when grown as a house plant it becomes necessary to mist the plant when relative humidity falls below around 80%. Although outdoors this plant prefers partial shade or full shade, inside it grows best in bright filtered light. This plant is usually propagated by division of the rooted runners, as named cultivars will not produce true spores. It is safe for cats to eat as it is known to be non-toxic.