Ant ferns are found in a number of genera. Some ferns provide nectar, while others provide shelter. The ants provide protection and nutrients to the plant.
Solanopteris is now considered to be a part of the genus microgramma. This is a South American genus that makes little appendages which are filled with material that the ants eat, creating a hollow space in which to live. Somewhat difficult to maintain in cultivation.
Lecanopteris form shelters in a variety of ways. Lecanopteris crustacea, luzonensis, curtisii, and sinuosa have hollow rhizomes, while Lecanopteris mirabilis rhizomes are like plates stacked on top of one another.
Lecanopteris celebica has a broad, flattened rhizome. Note the small spines on the rhizome in the upper picture.
Lecanopteris crustacea has flattened rhizomes, covered with round scales.
Lecanopteris curtisii rhizomes are similar to luzonensis, but they are light green, with what looks like a blue coating.
The species below, Lecanopteris luzonensis, has been called Lecanopteris carnosa. It seems Lecanopteris carnosa may not be in cultivation, at least not in the U.S.
Lecanopteris mirabilis is unusual in that it does not have hollow rhizomes. Rather, it forms plates which grow on top of each other, providing hiding places for ants. This species is difficult to maintain. It suffers in high temperatures.
Lecanopteris 'Alford' (not pictured) This odd fern came up in a sowing of Lec. mirabilis spores, which I obtained from Nick Plummer. It has rhizome scales like mirabilis, but is certainly not typical of that species. See the Lecanopteris hybrid at Nick's site, http://home.nc.rr.com/myrmecophyte/lec_hybrid.html This cultivar has not been easy to grow. It is very vigorous when happy, but seems susceptible to rots.
Lecanopteris pumila is a little smaller than the other lecanopteris I grow. The rhizomes are similar to Lecanopteris luzonensis.