Introducing Conifers

Abstract

Summary Conifers are cone-bearing seed plants with an ancient evolutionary history. Opening with an introduction to Australia's Wollemi pine, one finds that modern conifer taxa (seven families, 71 genera, 620+ species) are persistent Mesozoic relics. As such, their evolutionary history begins with the terrestrial invasion of land plants and the greening of the earth, the rise of the Paleozoic forest and the Jurassic plant diet of herbivorous dinosaurs. All modern conifers, not just Wollemi pine (Wollemia nobilis), are living fossils. Conifers have persisted despite continental drift, climate oscillations, volcanism and the rapid spread of angiosperms. Modern conifers, as a whole, are distributed worldwide although a few regions of the world such as China, Mexico and New Caledonia have high concentrations of conifer taxa. Although many conifer species have large, wideranging census populations, others such Wollemi pine are critically endangered. Vestiges of the ancient conifer diaspora can be seen in the fossilized Metasequoia-dominated forests in Canadian High Arctic and from the endemic Da Lat ecosystem in Vietnam which includes the flat-leaved Pinus krempfii. Conifers are among the oldest extant seed plant lineage and their peculiar reproductive biology holds clues about seed plant evolution.