Plesioneuron altum (Brause) Holttum

Fawcett, Susan & Smith, Alan R., 2021, A Generic Classification of the Thelypteridaceae, Fort Worth, Texas, USA: BRIT Press : 67

Constituent species.— Plesioneuron altum (Brause) Holttum ; P. angiense Holttum ; P. angusticaudatum (Holttum) S.E. Fawc. & A.R. Sm. ; * P. archboldiae (Copel.) Holttum ; * P. attenuatum (Brack.) Holttum ; * P. belense (Copel.) Holttum ; P. bipinnatum (Copel.) Holttum ; P. caudatum (Holttum) S.E. Fawc. & A.R. Sm. ; * P. costulisorum (Copel.) Holttum ; P. crassum (Copel.) Holttum ; P. croftii Holttum ; P. cystodioides Holttum ; P. deficiens (Holttum) S.E. Fawc. & A.R. Sm. ; P. doctersii Holttum ; P.dryas Holttum ; P. dryopteroideum (Brause) Holttum ; P.excisum (Holttum) S.E. Fawc.& A.R. Sm. ; * P. falcatipinnulum (Copel.) Holttum ; P. finisterrae (Brause) S.E. Fawc. & A.R. Sm. ; P. fuchsii Holttum ; P. fulgens (Brause) Holttum ; * P. hopeanum (Baker) Holttum ( Fig. 6A ); * P. imbricatum (Holttum) S.E. Fawc. & A.R. Sm. ( Fig. 2I ); * P.keysserianum (Rosenst.) S.E. Fawc. & A.R.Sm. ; P. kostermansii Holttum ; P.kundipense Holttum ; P.ligulatum (J. Sm. ex C. Presl) S.E. Fawc. & A.R. Sm. ; * P. marquesicum Holttum ; P. medlerae (W.N. Takeuchi) S.E. Fawc. & A.R. Sm. ; P. medusella Holttum ; P.mingendense (Gilli) S.E. Fawc. & A.R. Sm. ; P.murkelense M. Kato ; P.myriosorum (Copel.) Holttum ; P.notabile (Brause) Holttum ; P. obliquum (Holttum) S.E. Fawc.& A.R. Sm. ; P.ophiura (Copel.) Holttum ; P.phanerophlebium (Baker) Holttum ; P. platylobum Holttum ; * P. ponapeanum (Hosok.) Holttum ; * P.prenticei (Carruth.) Holttum ; P.pullei Holttum ; P. quadriquetrum (Alderw.) Holttum ; P.regis (Copel.) S.E. Fawc. & A.R. Sm. ; P. rigidilobum Holttum ; Plesioneuron royenii Holttum ; P. sandsii Holttum ; * P. savaiense (Baker) Holttum ; P. saxicola M. Kato ; P. septempedale (Alston) Holttum ; P. stenura Holttum ; * P. subglabrum Holttum ; P. subterminale Holttum ; * P. tahitense Holttum ; P. translucens Holttum ; * P. tuberculatum (Ces.) Holttum ; P. varievestitum (C. Chr.) Holttum ; P. walkeri (Holttum) S.E. Fawc. & A.R. Sm. ; P. wantotense (Copel.) Holttum ; P. wariense (Copel.) Holttum ; P.woodlarkense (Copel.) Holttum

Incertae sedis.— Trigonospora koordersii (Christ) Holttum was initially included in Mesophlebion subg. Plesioneuron ( Holttum 1971) , but later Holttum (1974c) decided that this taxon shared a close resemblance to Trigonospora calcarata . This plant is known only from the type collection (L, image!), and it is unclear whether that specimen may yield spores that could verify its placement in Trigonospora . At the present time, we cannot rule out its placement in Plesioneuron .

Figures

FIG. 6. A. Plesioneuron hopeanum, Fawcett 613 (VT),pinna lobes,adaxial view.Amauropelta (subg.Nibaa) noveboracensis, Fawcett 567 (MICH,VT),B. pinna-lobes, adaxial view.C.habit.D. Thelypterispalustris,Fawcett 569 (VT),pinna lobes abaxial view.

FIG. 2. Morphology of the Thelypteridaceae.A. Coryphopteris kolombangarae, SITW07554 (TAIF), glandular indusia.B. Goniopteris yaucoensis, Proctor 43584 (US), stellatehairs along adaxialcosta.C.Pneumatopterisglandulifera,SITW11069 (TAIF),peg-like aerophoresat pinna bases.D.Sphaerostephanospolycarpos,SITW11070 (TAIF),marginally glandular indusia.E.Sphaerostephanos doodioides,SITW05702(TAIF),setoseindusia,spherical glands on indusia,sporangia,and laminar tissue. F. Goniopteris reptans, Wright 813 (US), sori with shriveled, setose indusia, some hairs furcate. G. Macrothelypteris polypodioides, SITW11122 (TAIF), stipe scales. H. Hoiokula pendens, Hobdy 2664 (UC), setulose sporangia. I. Plesioneuron imbricatum, SITW05370 (TAIF), exindusiate sori, sporangia with spherical glands. J. Christella dentata, SITW10525 (TAIF), shriveled,setulose indusia.K. Sphaerostephanos heterocarpos SITW11079 (TAIF),abruptly reduced proximal pinnae,adaxial surface with acicular hairs.L. Coryphopteris subbipinnata, SITW11667 (TAIF),appressed stipe base scales,these marginally setulose.All photos by Cheng-Wei Chen except B,F,and H by Susan Fawcett.