A genus of ornamental tree Ferns from temperate and tropical regions, chiefly valuable for the decoration of large conservatories, etc, where plenty of space is available. Amongst the best-known kinds are A. excelsa, which is practically hardy in the mildest parts of the kingdom; A. Rebeccae, from Australia, another fairly hardy species; A. australis, a beautiful Australian tree Fern requiring coolhouse treatment; while A. aculeata (or ferox) and A. armata, both from Tropical America, should be grown in the stove.