Class CONIFEROPSIDA
Description: The Coniferopsida are terrestrial trees or shrubs which do not form flowers but reproduce sexually by seeds that are naked (that is, not formed within an ovary). The sporophyte consists of true roots, stems and true leaves.
The leaves are simple (often needle-like) or reduced and scale-like and are either spirally arranged or opposite and decussate. The woody stems are branched and give rise to long and short shoots; resin canals are often present in leaves and stems.
The plants are usually dioecious with the reproductive organs borne on specialized leaves (sporophylls) which are usually arranged in cones or cone-like structures. The gametophyte stage is microscopic and enclosed within the cones or cone-like structures produced by the sporophyte. The pollen forms within the microsporangia on the scales (microsporophylls) of the male cones. The ovules are borne on the sporophylls of the female cones and the pollen is usually transferred to the ovules by wind.
After fertilization the seed develops directly on the female sporophyll without a protective pericarp. The seeds are often winged and the embryo has two to many cotyledons.
Distribution and occurrence: World: 7 families, c. 70 genera, >600 species, widespread, especially prominent in northern temperate regions. Australia: 4 families, 17 genera, c. 57 species, all States.
Sometimes ranked as a Division, Pinophyta.
Text by G.J. Harden
Taxon concept:
| | Key to the class CONIFEROPSIDA | |
| 1 | Ovules solitary and exposed on ± fleshy stalks (reduced cones) that are borne singly or in spikes, or in very small, terminal, fleshy or dry, but never woody, cones; one ovule on each scale | PODOCARPACEAE |
| Ovules in definite cones that become woody in fruit; 1–many ovules on each scale | 2 |
| 2 | Leaves and cone scales spirally arranged, the latter imbricate; leaves usually free from the stem | 3 |
| Leaves and cone scales opposite or whorled, the latter usually valvate; leaves often appressed to the stem, bases decurrent
Back to 1 | CUPRESSACEAE |
| 3 | Ovule 1 on each scale; male sporophylls with several to many sporangia; leaves <2 cm long, or if longer then >5 mm wide | ARAUCARIACEAE |
| Ovules 2 on each scale; male sporophylls with 2 sporangia; leaves >10 cm long and <3 mm wide
Back to 2 | PINACEAE |
|
