Mengea californica Moquin-Tandon (1849: 270−271)

Iamonico, Duilio, 2016, Nomenclature survey of the genus Amaranthus (Amaranthaceae). 5. Moquin-Tandon’s names, Phytotaxa 273 (2), pp. 81-114 : 108-109

43. Mengea californica Moquin-Tandon (1849: 270−271) ≡ Amaranthus californicus (Moq.) S.Watson (1880: 42)

Type (lectotype here designated):— U.S.A. California, 1848, Hartweg 193 (G barcode G00201669 [digital image!], image of the lectotype is available at http://www.ville-ge.ch/musinfo/bd/cjb/chg/adetail.php?id=159512&base=img&lang=en).

Nomenclatural notes: — The protologue of Mengea californica ( Moquin-Tandon 1849: 270−271) consists of a detailed dagnosis, the provenance (“ In California ”), and the collector information (“ Hartw.! 1930 ”). I found at G one specimen (barcode G00201669) bearing one plant (synflorescence part), and the original labels had the data: “ 1930 ” (pinned over than the exsiccatum, about on the center of the sheet), and “ California Hartweg 1848 ” (pinned at the base of the plant). Although the annotations on exsiccatum at G (locality of collection, collector and the collection number) completely match the data reported in the protologue, according to McNeill (2014) I cannot be sure that this specimen is the only one in extant. As a consquence, I here designated the specimen G00201669 as the lectotype of the name Mengea californica .

Taxonomical notes: — This species is currently accepted under Amaranthus as Am. californicus (Moq.) S.Watson (see e.g. Mosyakin & Robertson 2003) and, according to the revision by Mosyakin & Robertson (1996), it belongs to the subgen. Albersia (Kunth) Gren & Godr. However, Mosyakin & Robertson (1996) have not included Am. californicus in any of the sections that they recognized. Actually, since Am. californicus have usually pistillate flowers with 1 welldeveloped tepals (sometime the tepals are absent, rarely are 2 or 3), I cannot currently placed this taxon at sectional level. According to Mosyakin & Robertson (1996), further sections and subsection of the subgen. Albersia could be recognized in future, and the taxa with 0‒1 tepal could represent a new group. Waiting further investigations on the related taxa with a reduced number of tepals ( Am. tenuifolius Willd. , and Mengea peruviana Schauer ), I prefer to avoid the circumscription of Am. californicus at sectional/subsectional level.