Gymnosperm identification: part-2

Pinophyta (or Coniferophyta):

The division Pinophyta is also known as Coniferophyta or Coniferae, or normally conifers is a division of vascular land plants containing a single extant class, Pinopsida. They are cone-bearing seed plants which seeds are not protected by the ovary or fruit, a subset of gymnosperms.

A great amount is trees, though a limited amount of are shrubs. Examples include cedars, Douglas firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews. As of 1998, the division Pinophyta was estimated to contain eight families, 68 genera, and 629 living species.

All habitation conifers are woody plants, and most are trees, the prevalence having monopodial growth form (a single, straight trunk with side branches) with robust apical distinction.

Since most conifers are evergreens, the leaves of several conifers are lengthy, thin, and have a needle-like impression, but others, encompassing most of the Cupressaceae and some of the Podocarpaceae, have flat, triangular scale-like leaves. A handful, notably Agathis in Araucariaceae and Nageia in Podocarpaceae, have broad, flat strap-shaped leaves. Others such as Araucaria columnaris have awl-shaped leaves. In the prevalence of conifers, the leaves are arranged spirally, exceptions being most of Cupressaceae and one genus in Podocarpaceae, where they are organized in decussate opposite pairs or whorls of 3 (−4).

In numerous varieties with spirally organized leaves, such as Abies grandis (pictured), the leaf bases are twisted to introduce the leaves in a very flat plane for ultimate light capture. Leaf size differs from 2 mm in several scale-leaved species, up to 400 mm long in the needles of some pines (e.g. Apache Pine, Pinus engelmannii).

We know there 12 families of gymnosperm among them 10 are living and 2 are extinct families.

But the interesting thing is that we found 8 families into Pinophyta (or Coniferophyta) division.

So, we can consider pinophyta as the largest division of gymnosperm.

Scientific classification:

Kingdom: Plantae

Clade: Tracheophytes

Clade: Spermatophytes

Division: Pinophyta

Class: Pinopsida

Orders and families:

A.Cordaitales

B.Pinales

1.Pinaceae

2.Araucariaceae

3.Podocarpaceae

4.Sciadopityaceae

5.Cupressaceae

6.Taxaceae

7.Cheirolepidiaceae

C.Vojnovskyales

D.Voltziales