Novel fern- and centipede-like Selaginella (Selaginellaceae) species and a new combination from South America

Abstract

Two new Selaginella species (i.e. S. altheae Valdespino and S. squamulosa Valdespino) and a novel combination [i.e. S. philipsonii (Jermy & Rankin) Valdespino] from South America are proposed. Descriptions, illustrations (line drawings and scanning electron micrographs, SEM, images), discussion on taxonomic affinities and information on habitat, distribution and phenology, as well as on conservation status are provided for each. Selaginella altheae is morphologically similar to species with erect, fern-like habit placed in the “Selaginella flabellata (L.) Spring group” as defined by Hieronymus, while S. squamulosa is allied to a species assembly with centipede-like habit here informally termed the “Selaginella vernicosa Baker group;” whereas S. philipsonii with its moss-like habit may be associated with species in the “Selaginella jungermannioides (Gaudich.) Spring group” or those centered on S. ovifolia Baker. All taxa here proposed are classified in subg. Stachygynandrum.

Taxonomic innovations in South American Selaginella (Selaginellaceae, Lycopodiophyta): description of five new species and an additional range extension

“… Selaginella gioiae , S. surucucusensis , and S. xanthoneura are morphologically related to the Neotropical “ Selaginella flabellata (L.) Spring group” as defined by Hieronymus (1901: 682) and Valdespino (2017a) . This group comprises some thirty-five species characterized by their fern-like habit, erect stems with leaves seemingly monomorphic before branches, as well as axillary, ventral, dorsal, and occasionally, seemingly lateral rhizophores.…”

“… Selaginella , a highly diverse and species rich lycophyte genus (600–800 spp), is found in a wide variety of ecosystems almost worldwide ( Valdespino 2015 ; Zhou and Zhang 2015 ; PPG I 2016 ; Valdespino 2016 ; Valdespino 2017a ). Selaginella species can be classified using several subgeneric classification systems as discussed in Valdespino and López (2019) .…”

From the Guiana Highlands to the Brazilian Atlantic Rain Forest: four new species of Selaginella (Selaginellaceae – Lycopodiophyta: S. agioneuma, S. magnafornensis, S. ventricosa, and S. zartmanii)

“…Additional virtual herbaria consulted included RB ( JBRJ, 2018 ), Reflora (2018) , and Species Link (2018) . Scanning electron microscopy (SEM) micrographs from selected specimens to document leaf surfaces and sculpturing patterns of mega- and microspores (when available), from designated holotypes were prepared, viewed, digitized and post-processed according to standard techniques using an image-handling software as referenced in Valdespino (2017a) and Valdespino (2017b) . Terminology, measurements, and conservation status provided for each taxon follow relevant glossaries ( Punt et al, 2007 ; Hesse et al, 2009 ; Beentje, 2016 ), and Valdespino (2016) , Valdespino (2017b) , and references therein.…”

“…Scanning electron microscopy (SEM) micrographs from selected specimens to document leaf surfaces and sculpturing patterns of mega- and microspores (when available), from designated holotypes were prepared, viewed, digitized and post-processed according to standard techniques using an image-handling software as referenced in Valdespino (2017a) and Valdespino (2017b) . Terminology, measurements, and conservation status provided for each taxon follow relevant glossaries ( Punt et al, 2007 ; Hesse et al, 2009 ; Beentje, 2016 ), and Valdespino (2016) , Valdespino (2017b) , and references therein. Nonetheless, we believe it appropriate to further explain some terms such as “ idioblasts ,” which refer to those cells that differ from surrounding ones in shape (i.e., in this case they are elongate), size or function (see Beentje, 2016 ), regardless of the chemical composition of their intercellular or cell wall projections, which look like a continuous stripe or line.…”

“…Such works have particularly improved our understanding of species distribution and diversity patterns at local, regional, and global scales. For example, Valdespino (2015a) ; Valdespino (2016) ; Valdespino (2017a) ; Valdespino (2017b) ; Valdespino (2017c) and Smith & Kessler (2018) established that the three South American countries with the richest Selaginella flora are in order: Venezuela (ca. 100 spp.…”