joelnitta
commented
1 year ago This proposal was voted on during PPG Ballot 2 (voting period August 2023). A total of 69 votes were cast. There were 67 'Yes' votes (97.1%) and 2 'No' votes (2.9%). The proposal passes.
Name of taxon
Adetogramma
Rank of taxon
Genus
Approximate number of species affected
1
Description of change
Adetogramma, a monotypic genus in Polypodiaceae, was described by Almeida et al. (2017) to accommodate Polypodium chrysolepis Hook. The species had been previously combined in Microgramna (Microgramma chrysolepis(Hook.) Crabbe).
Reason for change
Phylogenetic inferences by Schneider et al. (2004) indicated that Polypodium chrysolepis was not related to Microgramma. Later phylogenetic and morphological evidence showed that Polypodium chrysolepis constitutes an isolated lineage among the neotropical polygrammoid ferns, close to Serpocaulon and the grammitids (Almeida et al. 2017). The results were later supported by the phylogenomic inference of Wei and Zhang (2022). Adetogramma can be distinguished by its entire leaves with free veins and peltate, pedicellate, and lanceolate paraphyses. It can be distinguished from Microgramma, by the anastomosing veins on the sterile fronds of the latter (vs. free veins in Adetogramma). Moreover, A. chrysolepis has lanceolate, peltate, long-stalked paraphyses while in Microgramma, paraphyses (if present) are hairlike or lanceolate and sessile, never stalked. Adetogramma can be readily distinguished from Serpocaulon by having free veins, non-clathrate scales, peltate scales covering the laminar surfaces, and peltate scales as paraphyses. These characers contrast with features of Serpocaulon species: regular anastomosing veins (goniophlebioid venation), clathrate scales, and the absence of scales in veins or laminar surface between veins or paraphyses, or if paraphyses are present, they are 2-3 celled glands. Adetogramma also resembles some Pleopeltis species in having entire laminae, long-creeping rhizomes, and peltate paraphyses. The main difference between Pleopeltis and Adetogramma chrysolepis lies in the shape of the paraphyses – ovate-lanceolate in Adetogramma vs. roundish in Pleopeltis. Furthermore, species of Pleopeltis with entire blades always have anastomosing veins. Polypodium s.s. can be distinguished from A. chrysolepis by its deeply-pinnatifid to pinnate leaves with free (in the Polypodium dulce complex species) to anastomosing veins, with a single included veinlet in each areole. Indument is also a useful character for separating A. chrysolepis, as Polypodium s.s. shows glabrous to pilose laminar surfaces and the paraphyses, when present, are filamentous or branched, while Adetogramma has scaly laminae and the paraphyses are pedicellate scales.
Reference(s) for publication of the name
Almeida TE, Salino A, Dubuisson J, Hennequin S. 2017. Adetogramma (Polypodiaceae), a new monotypic fern genus segregated from Polypodium. PhytoKeys 78: 109–131. DOI: 10.3897/phytokeys.78.12189
Crabbe JA. 1967. Bolivian pteridophytes collected by Winifred Brooke. Fern Gazette 9: 309–320.
Schneider H, Smith AR, Cranfill R, Hildebrand TJ, Haufler CH, Ranker TA. 2004. Unraveling the phylogeny of polygrammoid ferns (Polypodiaceae and Grammitidaceae): exploring aspects of the diversification of epiphytic plants. Molecular Phylogenetics and Evolution 31(3): 1041–1063. DOI: 10.1016/j.ympev.2003.09.018
Wei R, Zhang X-C. 2022. A revised subfamilial classification of Polypodiaceae based on plastome, nuclear ribosomal, and morphological evidence. Taxon 71(2): 288-306. DOI: 10.1002/tax.12658
Almeida_et_al_2017_Adetogramma.pdf
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