While many patent examiners prefer Markush claims, which recite lists of alternatively useable species, to be formatted as “selected from the group consisting of A, B, and C,” Applicants should carefully consider claim construction before adopting this format. “A trap for the unwary claim drafter using Markush group language is the severely closed nature of a Markush group.” 3-8 Chisum on Patents § 8.06 (2017).
