editorial

The application of the name Oxalis megalorrhiza Jacq. to New Zealand plants requires reassessment. Oxalis mirbelii Dehnh. has historically been confused with O. megalorrhiza. Shaw (2022) distinguishes O. mirbelii by its bright green rather than glaucous-green leaflets, fewer-flowered inflorescences, and abundant seed production. Oxalis mirbelii is self-compatible and readily produces fertile seed, whereas O. megalorrhiza is not known to be self-fertile. Fresh and pressed material from Whanganui previously referred to O. megalorrhiza appears to agree better with O. mirbelii, including the production of fertile seed. This raises the possibility that some, or potentially all, New Zealand records currently identified as O. megalorrhiza may represent O. mirbelii. Existing CHR specimens require critical re-examination before the status of O. megalorrhiza in New Zealand can be resolved. Some diagnostic characters, particularly leaflet colour, glossiness and glaucousness, are difficult to assess in dried specimens. Fresh material from established New Zealand populations would therefore be particularly valuable for confirming identifications. Reference: Shaw, J.M.H. (2022). Oxalis (Oxalidaceae). In: Eggli, U. & Nyffeler, R. (eds), Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants. Springer, Cham.