What were the subgroups to plants

Explanation:

The division comprises a tremendous diversity of plants among its four subgroups: psilopsids, leafless and rootless primitive forms commonly known as whisk ferns (though not true ferns); sphenopsids, feathery leaved plants commonly called horsetails; lycopsids, low-lying plants called club mosses; and pteropsids, 

it takes hundreds of years to become stable.

if you have another question lmk.

i would say it is