Molecular systematics of the Asplenium nidus complex from Mt. Halimun National Park, Indonesia: Evidence for reproductive isolation among three sympatric rbcL sequence types

Asplenium nidus is an epiphytic fern with large simple leaves. Because A, n idus lacks the good taxonomic characters available for species recognition, multiple cryptic species may exist within A. nidus. In Mt. Halimun Nationa l Park, West Java, Indonesia, three rbcL sequence types of A. nidus were re corded. All plants regardless of rbcL sequence were 2n = 144. Crossing expe riments among these rbcL types were conducted, and it was observed that the molecularly distinct types were reproductively isolated because hybrids fa iled to form between at least two pairs of rbcL types. These results sugges t that these rbcL types are cryptic species because they are reproductively isolated but they are difficult to distinguish morphologically. Thus, the characters of DNA sequences information are useful in the discovery of cryp tic species in ferns.