Dacrycarpus is a genus of nine species of dioecious evergreen conifers in the family Podocarpaceae, order Coniferales. Trees and shrubs in this genus reach up to 41–60 metres in height, making Dacrycarpus dacrydioides (kahikatea) — the sole New Zealand representative — both the largest and tallest member, with individuals recorded living over 700 years.
The genus is recognised by its distinctly dimorphic foliage. Juvenile leaves are bilaterally flattened, falcate, and arranged distichously along the shoot in a feather-like pattern, typically 6–12 mm long. Adult leaves are shorter, more robust, and spirally arranged, with an apiculate tip bent forward parallel to the shoot. Bark is hard, dark brown to blackish, weathering to gray. The plants are dioecious: pollen cones are small and elongate at maturity; seed-bearing structures sit on short lateral shoots, with a fleshy receptacle that turns orange, red, or purple when ripe. The seed is nearly spherical and enclosed by a leathery epimatium fused to the fertile bract — a feature unique to the genus that distinguishes it from the closely related Dacrydium, whose seeds are naked.
Dacrycarpus was formally described by de Laubenfels in 1969, when eight species were segregated from Podocarpus and one new species (D. expansus) was described. The type species is D. imbricatus. The genus has an ancient fossil record extending to the Middle Jurassic of New Zealand and Patagonia, and was once present in Antarctica and SE Australia, where it is now extinct.
Etymology
The genus name Dacrycarpus derives from the Greek words for "tears" (dakry) and "fruit" (karpos), referring to the shape of the seed cones.
Distribution
Dacrycarpus ranges from northern Burma and southern China south and east through the Philippines, Malaysia, Indonesia, New Guinea, New Caledonia, Fiji, and New Zealand. The greatest species diversity — five of the nine species — is concentrated in New Guinea. D. dacrydioides is the sole species native to New Zealand.
Taxonomy Notes
The genus was described by de Laubenfels (1969), who segregated eight species from Podocarpus and described one new species. Synonyms include Podocarpus sect. Dacrydioideae Bennett, sect. Dacrycarpus Endl., and sect. Dacrydium Bertrand. The type species is Dacrycarpus imbricatus (Blume) de Laub. (basionym Podocarpus imbricatus Blume). The fusion of the fertile scale with the epimatium is a morphological trait unique to this genus within Podocarpaceae.
History
Dacrycarpus has a fossil record extending to the Middle Jurassic of New Zealand and the Upper Cretaceous to Oligocene of southern Patagonia, where the genus is now extinct. It is also recorded from Eocene and Oligocene deposits in southeastern Australia, where it likewise became extinct. Fossil material is known from Graham Land in northern Antarctica. The genus was formally revised and segregated from Podocarpus by de Laubenfels in 1969.
