Geoscience Reference
In-Depth Information
A treasure trove of shells collects in the swash zone of Island Beach, New Jersey.
PRECOCIOUS CONIFERS AND DOMINANT DECIDUOUS TREES
CONIFERS WERE
the first trees to evolve, 250 to 265 million years ago, from ancient gymno-
sperms—nonflowering naked seed plants. These upland plants descended into the lowlands as the great
swamplands, lakes, and flood plains of the Coal Age began to dry out in the Permian. Each tree usually con-
tains male and female cones. The male cones release millions of spores to fertilize the female cone, a repro-
ductive strategy that harkens back to marine plants. The wind-borne spores are released in the spring, and the
seeds mature in the fall, usually in the same year in which pollination occurs, though pine seeds mature after
two growing seasons. The seeds, which have one or two wings, are dispersed on the wind and, in temperate
zones, require a chilling period before germination.
The angiosperms, or flowering plants, arose in the mid-Cretaceous, about 100 million years ago, and include
the deciduous trees, whose ancestors did not appear until the end of the Cretaceous. The angiosperms proved
