| Name | Cystopteris fragilis var. mackayii G. Lawson |
| Authorship | G. Lawson |
| Rank | Variety |
| NomenclaturalStatus | NomLeg |
| Placed in | Cystopteris fragilis (Linnaeus) Bernhardi |
| Citation | 1889 Fern Fl. Canada 233 |
| Holdings | 8 Specimens held in the Harvard University Herbaria identified as Cystopteris fragilis var. mackayii G. Lawson |
| Identification made in | [no date] (3), 1935 (2), 1936 (3) |