Progymnospermophyta

Progymnospermophyta Temporal range: Middle Devonian to Mississipian
Archaeopteris fossil leaves
Scientific classification
Kingdom:	Plantae
Subkingdom:	Embryophyta
Division:	†Progymnospermophyta
Class:	Progymnospermopsida
Orders
Aneurophytales Protopityales Archaeopteridales

Progymnospermophyta is an extinct division of Paleozoic plants. Its sole class is Progymnospermopsida.

Characteristics

• Vascular cambium with unlimited growth potential is present as well as xylem and phloem.
• Ancestors of the earliest seed plants as well as the first true trees.
• Superficially conifer/spruce-like in appearance.
• Strong monopodial growth is exhibited.
• Macrophylls present as well as simple leaves.
• Some were heterosporous but others were homosporous.

External links

• Progymnospermophyta
• http://books.google.com/books?id=0DfYJsVRmUcC&pg=PA723&lpg=PA723&dq=Progymnospermophyta&source=bl&ots=8gLDGKNZ3U&sig=K86Hb_ITkTlATOtMQpJrByaMx3w&hl=en&sa=X&oi=book_result&resnum=7&ct=result