Morphological and molecular concordance for the recognition of two speciesin the New Zealand Polystichum richardii (Hook.) J. Smith complex

The New Zealand fern Polystichum richardii is shown to comprise at least tw o evolutionary lineages. A narrow-scaled morphological form and a wide-scal ed morphological form are recognised. Principal Component Analysis of a set of frond, soral and spore characters supports this morphological separatio n. Amplified Fragment Length Polymorphism (AFLP) DNA fingerprinting shows t hat the two morphological forms are also genetically distinct. They are sym patric across a broad area of central New Zealand, and often grow together without apparent ecological separation at the local level. Both are known t o form sterile hybrids with P.vestitum, suggesting that both morphological forms of P. richardii are at least partially outcrossing. The morphological and genetic distinctiveness of these two morphological forms, combined wit h their sympatric distributions and their (at least partially) outcrossing mating systems, merits their recognition as separate species.