Which of the following plant group first formed true leaves?

Explanation

Lycopsida were the first vascular plant group to develop true leaves, called microphylls, which have a single unbranched vein. Psilopsida were traditionally described as leafless, while Sphenopsida and Pteropsida appeared later. Students may choose Pteropsida because their leaves are larger and more familiar, but they were not the first to form leaves.