sentence1: In 1881 , he married Agnes Theodora Walther , daughter of Vilhelm Theodor Walther , and his son is the botanist and draftsman Vagn Petersson .
sentence2: In 1881 , he married Agnes Theodora Walther , daughter of Vagn Petersson , and his son is the botanist and sketch artist Vilhelm Theodor Walther .