Gymnosperm identification: part-1

What is gymnosperm?

A plant of a group that comprises those that have seeds. But the seeds are not protected by an ovary or fruit.

The gymnosperms, also known as Acrogymnospermae.

Examples: conifers, cycads, Ginkgo, and gnetophytes.

They are alive from the Carboniferous period to the present ( Holocene period). That means they crossed the Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleogene, Neogene period and are still alive today( Holocene period)

There almost 13 periods. And they are:

Precambrian, Cambrian Period, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleogene, Neogene, Holocene.

Scientific classification of gymnosperm:

Kingdom: Plantae

Subkingdom: Embryophyta

(unranked): Spermatophyta

(unranked): Gymnospermae (inc. †; paraphyletic) Acrogymnospermae (extant only).

Divisions of gymnosperm:

Pinophyta (or Coniferophyta) – Conifers

Ginkgophyta – Ginkgo

Cycadophyta – Cycads

Gnetophyta – Gnetum, Ephedra, Welwitschia

The extant gymnosperms include 12 main families and 83 genera which contain more than 1000 known species.

Subclass Cycadidae

1.Order: Cycadales

• Family: Cycadaceae: Cycas
• Family: Zamiaceae: Dioon, Bowenia, Macrozamia, Lepidozamia, Encephalartos, Stangeria, Ceratozamia, Microcycas, Zamia.

Subclass Ginkgoidae

1.Order: Ginkgoales

• Family: Ginkgoaceae: Ginkgo

Subclass Gnetidae

1.Order: Welwitschiales

• Family: Welwitschiaceae: Welwitschia

2.Order: Gnetales

• Family: Gnetaceae: Gnetum

3.Order: Ephedrales

• Family: Ephedraceae: Ephedra

Subclass Picidae

1.Order: Pinales

• Family: Pinaceae: Cedrus, Pinus, Cathaya, Picea, Pseudotsuga, Larix, Pseudolarix, Tsuga, Nothotsuga, Keteleeria, Abies

2.Order: Araucariales

• Family: Araucariaceae: Araucaria, Wollemia, Agathis
• Family: Podocarpaceae: Phyllocladus, Lepidothamnus, Prumnopitys, Sundacarpus, Halocarpus, Parasitaxus, Lagarostrobos, Manoao, Saxegothaea, Microcachrys, Pherosphaera, Acmopyle, Dacrycarpus, Dacrydium, Falcatifolium, Retrophyllum, Nageia, Afrocarpus, Podocarpus

3.Order: Cupressales

• Family: Sciadopityaceae: Sciadopitys
• Family: Cupressaceae: Cunninghamia, Taiwania, Athrotaxis, Metasequoia, Sequoia, Sequoiadendron, Cryptomeria, Glyptostrobus, Taxodium, Papuacedrus, Austrocedrus, Libocedrus, Pilgerodendron, Widdringtonia, Diselma, Fitzroya, Callitris, Actinostrobus, Neocallitropsis, Thujopsis, Thuja, Fokienia, Chamaecyparis, Cupressus, Juniperus, Calocedrus, Tetraclinis, Platycladus, Microbiota
• Family: Taxaceae: Austrotaxus, Pseudotaxus, Taxus, Cephalotaxus, Amentotaxus, Torreya.

Extinct groupings

1.Order: Bennettitales

• Family: Cycadeoidaceae
• Family: Williamsoniaceae

2.Order: Erdtmanithecales

3.Order: Pentoxylales

4.Order: Czekanowskiales