Ant-houses in the fern genus Lecanopteris Reinw. (Polypodiaceae): the rhizome morphology and architecture of L. sarcopus Teijsm. & Binnend. and L. darnaedii Hennipman

The rhizome morphology and architecture of L. sarcopus Teijsm. & Binnend. and L. darnaedii Hennipman. The rhizomes of the epiphytic fern Lecanopteris are highly modified and shelter ants, either in cavities or between the rhizome underside and the host tree. Different emphases on the relative contributions of morphology and architecture to the form of the ant-house exist in the genus, and are illustrated by a discussion of the rhizomes of L. sarcopus and L. darnaedii from Sulawesi, Indonesia. Lecanopteris sarcopus has dimorphic rhizomes, differentiated into solid, frond-bearing sections and hollow, frondless, ramifying ant-house branches. The internal morphology is simple; complexity in the rhizome structure is the result of profuse growth and branching of the ant-house branches. The rhizome of L. darnaedii is internally differentiated into two gallery and chamber systems, arranged vertically, with one directly above the other and running the length of the rhizome. Lecanopteris darnaedii does not branch profusely; 90–100% of primary side shoots develop but do not commonly grow beyond four to five internodes. Thus, in L. darnaedii plant architecture is restrained but morphology is intricate, while the reverse is true for L. sarcopus. Both species are equally regularly inhabited by ants.