Contrasts in crown development of the mistletoesAlepis flavida(Hook. f.) Tiegh. andPeraxilla tetrapetala(L. f.) Tiegh. (Loranthaceae) parasitic onNothofagus solandri(Hook. f.) Oerst., Craigieburn Ecological District, New Zealand

Publisher Website
Google Scholar
Abstract
The developmental features of Alepis flavida and Peraxilla tetrapetala, two parasitic Loranthaceae mistletoes endemic to New Zealand, are described for a better understanding of their comparative ecologies. The two species were found to have strikingly different modes of development. Alepis flavida develops monopodially from preformed buds, with little branching, while Peraxilla tetrapetala develops sympodially, and frequently bifurcates, after shoot-tip abortion from submerged buds with little preformed content, and with much branching. These two patterns produce distinctly different clump forms: loose clumps, with long limbs and few orders of branches, in Alepis flavida, and densely branched clumps, with many orders of branching, in Peraxilla tetrapetala. Both species produce runners, but in Peraxilla tetrapetala these spread to adjacent locations (often the trunk) and produce extremely large, multiple clumps, whereas Alepis flavida remains on the branch on which it established. This difference in development allows these two species to exploit similar niches in Nothofagus solandri forests. The developmental differences observed here support the taxonomic segregation of Alepis and Peraxilla.