What is "thalamiflorae"

Thalamiflorae is a historical grouping of dicotyledons, arranged in the De Candolle system and in the Bentham and Hooker system. This group was named and published well before internationally accepted rules for botanical nomenclature. In these systems, a family was indicated as "ordo", and modern rules of botanical nomenclature accept that as meaning a family rather than an order. Family names have also since been standardized (most family names now end in -aceae).