(approximate number of species in parentheses) The order Pinales in the division Pinophyta, class Pinopsida, comprises all the extant conifers.

All of the extant conifers, such as Araucaria, cedar, celery-pine, cypress, fir, juniper, kauri, larch, pine, redwood, spruce, and yew, are included here.

In his classification, Gymnospermae (alternatively named Archespermae) was a class of the division Archegoniatae, divided into subclasses;[1] A system of two groups was maintained by the most commonly used classification in the twentieth century,[13] the revision of the Engler system by Pilger (1926), who grouped 12 families of the Gymnospermae subdivision into 2 classes;[14] The treatment of Gymnosperms as two groups, though with varying composition and names, was followed for most of the twentieth century, including the systems of Chamberlain (1935),[15] Benson (1957)[16] and Cronquist (1960).

[17] In the latter, Cronquist divided Gymnospermae into two divisions; Benson,(1957)[16] who introduced the term Pinales, divided gymnosperms into four classes;[9] In a later revision, in collaboration with two other taxonomists (1966), Cronquist merged all the gymnosperms into a single division, Pinophyta, with three subdivisions reflecting the main lineages;[18][9] In the era of molecular phylogenetics, De-Zhi and colleagues (2004) once again proposed a division of 12 gymnosperm families into two classes;[9] With the development of the Angiosperm Phylogeny Group came a major realignment of the linear classification of the land plants, by Chase and Reveal (2009).

Subclasses (number of orders);[19] Gymnosperm (Acrogymnospermae) taxonomy has been considered controversial, and lacks consensus.

[29] Christenhusz and colleagues extended the system of Chase and Reveal[19] to provide a revised classification of gymnosperms in 2011, based on the above four subclades.

[2] In this scheme, the Pinidae comprise three orders, including Pinales, and 6 families; However, the exact phylogeny remained a topic that was 'hotly debated", in particular whether the main lineages were best represented by the four subclasses of Christenhusz and colleagues or the more traditional five clades (cycads, ginkgos, cupressophytes, Pinaceae and gnetophytes).

This established cycads as the basal group, followed by Ginkgoaceae, as sister to the remaining gymnosperms, and supporting the ‘gnepine’ hypothesis.

[31] Cycadidae (Cycadales) Ginkgoidae (Ginkgoales) Pinidae (Pinales) Gnetidae Sciadopityaceae Araucariaceae Podocarpaceae Taxaceae (including Cephalotaxaceae) Cupressaceae s.l.

[27] Christenhusz and colleagues (2011) included only one family in Pinales, Pinaceae,[2] a practice subsequently followed by the Angiosperm Phylogeny Website[33] and the Gymnosperm Database.