Note: Maggs & Guiry (1989) pointed out that Petrocelis J. Agardh, Cruoriopsis Dufour, and Haematocelis J. Agardh, which were included in the Cruoriaceae by Kylin (1956: 242), are to be referred elsewhere, leaving the family monotypic. They showed that the life history of the type species of Cruoria, C. pellita (Lyngbye) Fries, consists of an alternation of isomorphic crustose tetrasporophytes and gametophytes, the latter being monoecious and bearing carposporophytes. The only other species of Cruoria known to share this life history is C. cruoriaeformis (P. Crouan & H. Crouan) Denizot. Several other species of Cruoria have been shown by culture studies to be crustose tetrasporophytes of algae with heteromorphic life histories that belong to families not closely related to the Cruoriaceae.
Cruoria (?) indica Hauck, 1888 [1886–1889]: 86 (type locality: "Comoro-Insel Johanna, Pomoni'' [Domoni, Ndzouani, Comoro Islands]).—Denizot, 1968: 170, fig. 156.— Lawson, 1980: 40 (`Crouania', in error).
INDIAN OCEAN DISTRIBUTION: Comoro Islands.
Note: Denizot (l.c.) noted that this species is almost certainly not referable to Cruoria.