Complex sentence: In 1816 he accompanied Hoppe on a botanical expedition to the Adriatic coast, then returned to Coburg to arrange his diaries, and in April 1817 continued his research with Hoppe in Tyrol and Carinthia.
Split into simpler sentences: In 1816 he accompanied Hoppe on a botanical expedition to the Adriatic coast. Afterwards he traveled to Coburg to arrange his diaries, and in April 1817 continued his research with Hoppe in Tyrol and Carinthia.