Rediscovery of Mazus lanceifolius reveals a new genus and a new species in Mazaceae

Abstract

Mazus lanceifolius (Mazaceae) is a perennial herb with opposite leaves and endemic to central China that has not been collected for 130 years. Rediscovery of this enigmatic species in the wild allows for determination of its phylogenetic position within Mazaceae. Phylogenetic reconstruction of Mazaceae based on DNA sequences from four plastid markers (matK, rbcL, rps16 and trnL-trnF) and nuclear ribosome ITS consistently showed that Mazus was not monophyletic. Mazus lanceifolius is in the most basal clade within Mazaceae, as sister to the remaining species of three recognized genera Dodartia, Lancea and Mazus. These results support the separation of M. lanceifolius from Mazus as a new genus, which was established here as Puchiumazus Bo Li, D.G. Zhang & C.L. Xiang. Meanwhile, a collection from Shennongjia Forestry District of Hubei Province, China, misidentified as “M. lanceifolius” in previous molecular study, is here revealed to represent an undescribed species of Mazus, i.e., M. fruticosus Bo Li, D.G. Zhang & C.L. Xiang, sp. nov. Morphologically, Puchiumazus is clearly distinct from the other three genera by having quadrangular to somewhat ribbed stems, and obviously opposite leaves. In addition, we provide a taxonomic key to the four genera of Mazaceae.

First record of the family Mazaceae (Lamiales) in Colombia and the clarification of the synonyms of Mazus pumilus

“…To determine the generic identity of the species, we consulted the pertinent literature on the taxonomy of the Lamiales (Cao Shu, 1998;Deng et al, 2019;Kew, 2021b) and the species of this order reported for Colombia (Bernal et al, 2016). For the circumscription of Mazus, we followed Xiang et al (2021).…”

“…26 species and three varieties currently recognized (Hong et al, 1998;Deng et al, 2016). This genus is characterized by its herbaceous habit, flowers with zygomorphic corollas, with one 2-lobed upper lip and one 3-lobed lower lip, and fruit usually completely enclosed in the calyx when mature (Xiang et al, 2021).…”

Findings to the flora of Russia and adjacent countries: New national and regional vascular plant records, 4

“…(APG IV 2016). Dodartia, Lancea and Mazus were once placed in the tradi tio nally circumscribed Scrophulariaceae but variably affiliated with tribe Gratioleae or Mimuleae (Xiang et al 2021).The genus Dodartia is characterized by having scale-like leaves and much-bran ched stems.…”

Mazus danxiacola (Mazaceae), a distinct new species endemic to Danxia landform in Jiangxi Province, eastern China

“…Zhang & C.L. Xiang (Stevens 2001 onwards;Xiang et al 2021). Among these, Dodartia, Lancea and Puchiumazus contains only sole or two species (Fischer 2004;Deng et al 2019;Xiang et al 2021), while Mazus includes 37 accepted species which are distributed mainly in Asia to Australasia (POWO 2022).…”

“…Xiang (Stevens 2001 onwards;Xiang et al 2021). Among these, Dodartia, Lancea and Puchiumazus contains only sole or two species (Fischer 2004;Deng et al 2019;Xiang et al 2021), while Mazus includes 37 accepted species which are distributed mainly in Asia to Australasia (POWO 2022). Nearly all species of Mazus are annual or perennial herbs (Hong et al 1998;Deng et al 2016), except the M. fruticosus Bo Li, D.G.…”