Aegialitis is a genus of two shrubby mangrove species, with one native to Southeast Asia and the other native to Australia and Papua New Guinea.
Description
The two species of the genus are woody mangrove shrubs or small trees that grow up to 2 to 3 m tall. The deciduous species have leafy stems with leathery leaves arranged alternately or spirally. The leaf margins are entire and have parallel veins.
The hermaphroditic flowers are pollinated by Hymenoptera, Lepidoptera, and Diptera. Flowers are arranged in terminal cymose racemous inflorescences. Individual flowers have five sepals arranged in a fused tube around the white gamopetalous corolla that has five petals fused into a short tube. The androecium consists of five stamens that are attached near the base of the corolla tube. The superior gynoecium has five carpels, each with a 1-celled pistil and unilocular ovaries. Fruit are dehiscent and have a spongy mesocarp.
Unlike other mangrove species, the members of Aegialitis generally do not have aerial roots.
Taxonomy
The genus Aegialitis was described by Robert Brown in his 1810 work Prodromus Florae Novae Hollandiae et Insulae Van Diemen when he described the single species A. annulata. The second species was described by William Roxburgh in the 1830s. A genus of grasses was given the same genus name in 1820 by Carl Bernhard von Trinius and later renamed Rostraria.
There have been several opinions on the proper placement of the genus in relation to the rest of the Plumbaginaceae, though most authors have noted its distinct characteristics make it difficult to place properly. In 1968 Igorj Alexandrovich Linczevski suggested that the genus be included in its own monotypic family, the Aegialitidaceae. The Plumbaginaceae has historically been divided into either two subfamilies or two tribes and each approach has offered a different perspective of the proper taxonomic relationship in the family. Through cladistic analysis using both genetic and...
