Research in our laboratory has shown that in species of Dennstaedtia, Hypolepis, and Microlepia, the earliest identifiable stage of leaf initiation involves a more or less well-defined localized expansion of the shoot apex at the future leaf site (Turner, 1985).
The development of terminal or dichotomous shoot branching has been described for Gleicheniaceae (Hagemann & Schulz, 1978), Lygodium (Mueller, 1982a), and Dennstaedtia (Imaichi, 1984).
Dichotomous branching patterns that superficially are similar to the above occur in species of Dennstaedtia and Microlepia.
Stevenson (1976a) also described the initiation of roots and root traces close to the shoot apex in Dennstaedtia and the association of the roots with stelar perforations, or "root gaps.
Leaf ontogeny and shoot branching of Dennstaedtia scabra.