A new synonym from Hawaii and lectotypification of Plagiothecium longisetum (Plagiotheciaceae)

Abstract

Plagiothecium mauiense was first described in 1927 by V.F. Brotherus, based on materials from Hawaii. It has, so far been, treated as a separate species. A detailed analysis of the original material housed in the New York Botanical Garden Herbarium (NY01256708) found the specimen to be characterised by a lack of metallic lustre; concave, asymmetrical, lanceolate to lanceolate-ovate leaves, shrunken in their dry condition; a straight, not denticulate, acute to apiculate apex; elongate-hexagonal cells in irregular transverse rows, 101–131 × 15–21 µm at mid-leaf; very lax areolation, with decurrencies composed of three rows of cells. These characteristics indicate that this species is identical to the original material of P. longisetum (e.g. H-SOL 1563 011; PC0132572). Hence, we propose that P. mauiense should be recognised as a new synonym of P. longisetum. In addition, a review of P. longisetum syntypes found one (H-SOL 1563 011) to have the same date of collection as the protologue, and to possess a quite abundant gametophyte turf with well-preserved sporophytes, indicating it to be fertile. Considering the above, we propose that specimen H-SOL 1563 011 be designated the lectotype of P. longisetum.

Figure 2 from: Wolski GJ, Proćków J (2021) Lectotypification of Plagiothecium mauiense, a Hawaiian synonym of Plagiothecium longisetum (Plagiotheciaceae). PhytoKeys 177: 11-15. https://doi.org/10.3897/phytokeys.177.64042

“…However, this now appears possible and is the purpose of the present paper. Wolski and Proćków (2020) confirmed that syntypes of P. mauiense are deposited in four American herbaria: Harvard University Herbarium (FH00220142), Miami University Herbarium (MU 000000546), New York Botanical Garden Herbarium (NY01256708) and Yale University Herbarium (YU 233890). Although it was possible to take on loan the described material from only two of them (Herbaria NY and YU), all four herbaria were able to provide the necessary assistance, as well as a wealth of data, including microscopic photographs of the described original material.…”

Lectotypification of Plagiothecium mauiense, a Hawaiian synonym of Plagiothecium longisetum (Plagiotheciaceae)

“… Wolski and Proćków (2020) confirmed that syntypes of P. mauiense are deposited in four American herbaria: Harvard University Herbarium (FH00220142), Miami University Herbarium (MU 000000546), New York Botanical Garden Herbarium (NY01256708) and Yale University Herbarium (YU 233890). Although it was possible to take on loan the described material from only two of them (Herbaria NY and YU), all four herbaria were able to provide the necessary assistance, as well as a wealth of data, including microscopic photographs of the described original material.…”

“…A detailed comparative taxonomic analysis of the qualitative and quantitative features of the original material confirmed that the name is synonymous with P. longisetum Lindb. Additionally, the conducted research found all original specimens of P. mauiense to be syntypes ( Wolski and Proćków 2020 ).…”

“…Unfortunately, to date, it was not possible to compare all known original material, so the lectotypification of P. mauiense was not completed ( Wolski and Proćków 2020 ). However, this now appears possible and is the purpose of the present paper.…”

Figure 1 from: Wolski GJ, Proćków J (2021) Lectotypification of Plagiothecium mauiense, a Hawaiian synonym of Plagiothecium longisetum (Plagiotheciaceae). PhytoKeys 177: 11-15. https://doi.org/10.3897/phytokeys.177.64042

“…Unfortunately, to date, it was not possible to compare all known original material, so the lectotypification of P. mauiense was not completed (Wolski and Proćków 2020). However, this now appears possible and is the purpose of the present paper.…”