From Echochi Scans:

Saitei na Anata to Aki no Sora (The Worst You and the Autumn Sky)
Nanami thinks his senior is a really awful guy, but still he can't help but like him. When his senior gets dumped, what will he do?

From Girls' Generation Scanlations:

Almost a year has passed since Tokio-sempai unexpectedly told Yousuke, a student and lover of plants, "I fell in love with you at first sight!" So every day, Yousuke is continually on the receiving end of Tokio’s relentless attacks. The handsome Tokio, who is also a good student and successful with girls, harasses Yousuke daily, pushing him farther and farther away... or maybe...

Also contains the short story Kamisama wo Yameru Toki (c.4).