Belongs within: Hypnales.
The Leskeaceae are a family of mosses found worldwide, traditionally distinguished by the possession of reduced peristomes and short laminal cells. Recently, the family as previously recognised was identified as polyphyletic by García-Avila et al. (2009), with the type genus Leskea nested within the Thuidiaceae. Leskea species are autoicous mosses with relatively few paraphyllia and erect capsules.
Characters (from Watson & Dallwitz): Gametophyte: Pleurocarpous; not dendroid; mostly forming patches, or forming wefts. Primary stems procumbent (the branches erect or procumbent). Shoots not complanate. Paraphyllia present (sparse or numerous), or absent. Pseudoparaphyllia absent. Stems not tomentose. The leaves of main stems and branches similar in form; ovate to lanceolate (concave); spiral; (sub-)secund (or the tips turned to one side, when moist), or not secund; double-nerved, or single-nerved. The leaf nerves not extending beyond the middle of the leaf, or extending beyond the middle of the leaf, but not to the tip. Leaf blade apices obtuse, or pointed; apically rounded, or apically acute, or acuminate. Leaf blade margins flat, or revolute or recurved; entire, or denticulate. Leaf blades not conspicuously bordered. The basal leaf cells more or less isodiametric to longitudinally much elongated; quadrate, or rectangular, or rounded, or rhomboidal to linear; papillose, or smooth. The walls of basal leaf cells thin, or thick; straight. The angular cells clearly differentiated, or not well differentiated. The mid-leaf cells more or less isodiametric to somewhat longitudinally elongated, or longitudinally much elongated; quadrate, or rectangular, or hexagonal, or rounded, or rhomboidal to vermicular; papillose, or smooth. The walls of the mid-leaf cells thin, or thick; straight. Plants monoecious, or dioecious; when monoecious, autoecious. Sporophyte: Capsules exserted; erect to inclined; symmetrical, or symmetrical to asymmetrical; straight, or curved; sub-cylindric to ovoid; smooth; with an annulus, or without an annulus. Calyptra symmetrical; splitting down one side. Capsules with a peristome. The peristome double. The peristome teeth joined basally to form a membranous ring, or not basally joined; not grouped; not deeply cleft; thin, membranous, and transversely barred; exteriorly with a fine longitudinal dividing line between the transverse bars. The inner peristome reduced to rudimentary; about equalling the outer to exceeding the outer; with a basal membranous ring (this short); with elongated “processes”; without cilia (or rudimentary). The operculum conical to rostrate. Setae long; straight.
<==Leskeaceae |--Leskeella (Limpr.) Loeske 1903OZB-O03 |--Claopodium (Lesq. & Jam.) Renauld & Cardot 1893SK02 | `--C. assurgens (Sull. & Lesq.) Cardot 1911SK02 |--Pseudoleskeopsis Broth. 1907SK02 | `--P. imbricata (Hooker & Wilson) Thér. 1929 (see below for synonymy)SK02 |--Lescuraea Schimp. in Bruch, Schimp. & Gümbel 1851S04 | `--L. saxicola (Schimp.) Milde 1869S04 (see below for synonymy) |--Ptychodium Schimp. 1860S04 | `--P. plicatum (Schleich. ex Weber & Mohr) Schimp. 1860S04 (see below for synonymy) |--LindbergiaN02 | |--L. koelziiN02 | `--L. longinervisN02 |--Haplocladium Müller 1899 [=Bryohaplocladium Watanabe & Iwatsuki 1981]OZB-O03 | |--H. microphyllum (Hedw.) Broth. in Engl. & Prantl 1907OZB-O03 | `--H. virginianumVH02 |--Leskea Hedw. 1801S04 | |--L. fuegianaD03b | |--L. gracilescensVH02 | `--L. polycarpa Hedw. 1801S04 (see below for synonymy) |--Pseudoleskiella Kindb. 1896S04 | |--P. catenulata (Brid. ex Schwägr.) Kindb. 1896S04 (see below for synonymy) | |--P. nervosa (Brid.) Nyholm 1960S04 (see below for synonymy) | |--P. rupestris (Berggr.) Hedenäs & Söderstrom 1991 (see below for synonymy)S04 | `--P. tectorum [=Leskeella tectorum]OZB-O03 `--Pseudoleskea Schimp. in Bruch, Schimp. & Gümbel 1852S04 |--P. fuegianaD03a |--P. incurvata (Hedw.) Loeske 1911S04 (see below for synonymy) |--P. laevifoliaN02 |--P. patens (Lindb.) Kindb. 1894S04 [=Lescuraea incurvata var. patensOZB-O03, Leskea patensD24] |--P. radicosa (Mitt.) Macoun & Kindb. 1892 (see below for synonymy)OZB-O03 `--P. rigescens [incl. P. stenophylla]D24 Nomen nudum: Leskea splendidula Hampe 1880 [=Rhaphidorrhynchum splendidulum Mitt. 1882, Rhaphidostegium splendidulum Paris 1897]SK02
Lescuraea saxicola (Schimp.) Milde 1869S04 [=Lesc. mutabilis var. saxicolaOZB-O03, Lesc. striata var. saxicolaOZB-O03, Lesquereuxia saxicolaD24, Pseudoleskea striata var. saxicolaD24; incl. P. striata var. mutabilisS04, Lesc. mutabilis (Brid.) Lindb. ex Hagen 1909OZB-O03, Lesc. saxicola var. mutabilisS04, Lesquereuxia mutabilisOZB-O03, Pterigynandrum mutabileOZB-O03, Anomodon striatusOZB-O03, Lescuraea striataOZB-O03, Neckera striataOZB-O03, Pseudoleskea striata D24, Pterogonium striatumD24]
Leskea polycarpa Hedw. 1801S04 [incl. L. polycarpa var. exilisOZB-O03, L. polycarpa var. paludosaOZB-O03, L. polycarpa var. tenellaOZB-O03]
Pseudoleskea incurvata (Hedw.) Loeske 1911S04 [=Lescuraea incurvataS04, Leskea incurvataOZB-O03; incl. Lesc. atrovirensOZB-O03, Leskea atrovirensOZB-O03, Lesquereuxia atrovirensD24, Pseudoleskea atrovirensS04, Hypnum filamentosumD24, Lesquereuxia filamentosaD24, Pseudoleskea filamentosaOZB-O03, Lescuraea incurvata var. tenellaOZB-O03]
Pseudoleskea radicosa (Mitt.) Macoun & Kindb. 1892 [=Lescuraea radicosa; incl. Lesc. incurvata var. brachyclados, Leskea brachyclados, Pseudoleskea atrovirens var. brachyclados]OZB-O03
Pseudoleskeopsis imbricata (Hooker & Wilson) Thér. 1929 [=Leskea imbricata, Cryphaea imbricata, Pseudoleskea imbricata; incl. Leskea calochlora, P. calochlora]SK02
Pseudoleskiella catenulata (Brid. ex Schwägr.) Kindb. 1896S04 [=Hypnum catenulatumD24, Leskea catenulataD24, Pseudoleskea catenulataS04; incl. Pseudoleskeella catenulata var. laxifoliaOZB-O03]
Pseudoleskiella nervosa (Brid.) Nyholm 1960S04 [=Hypnum nervosumOZB-O03, Leskea nervosaS04, Leskeella nervosa (Brid.) Loeske 1903S04, OZB-O03, Pterogonium nervosumD24]
Pseudoleskiella rupestris (Berggr.) Hedenäs & Söderstrom 1991 [incl. Pseudoleskea catenulata var. acuminata, Pseudoleskiella catenulata var. acuminata, Pseudoleskiella sibirica]S04
Ptychodium plicatum (Schleich. ex Weber & Mohr) Schimp. 1860S04 [=Brachythecium plicatumS04, Hypnum plicatumD24, Lescuraea plicataS04, Lesquereuxia plicataD24, Pseudoleskea plicataOZB-O03; incl. Ptychodium plicatum f. homomalumOZB-O03]
*Type species of generic name indicated
References
[D24] Dixon, H. N. 1924. The Student’s Handbook of British Mosses 3rd ed. V. V. Sumfield: Eastbourne.
[D03a] Dusén, P. 1903. The vegetation of western Patagonia. In: Scott, W. B. (ed.) Reports of the Princeton University Expeditions to Patagonia, 1896–1899 vol. 8. Botany pp. 1–34. The University: Princeton (New Jersey).
[D03b] Dusén, P. 1903b. Patagonian and Fuegian mosses. In: Scott, W. B. (ed.) Reports of the Princeton University Expeditions to Patagonia, 1896–1899 vol. 8. Botany pp. 63–126. The University: Princeton (New Jersey).
García-Avila, D., E. De Luna & A. E. Newton. 2009. Phylogenetic relationships of the Thuidiaceae and the non-monophyly of the Thuidiaceae and the Leskeaceae based on rbcL, rps4 and the rps4-trnS intergenic spacer. Bryologist 112 (1): 80–93.
[N02] Negi, H. R. 2002. Abundance and diversity of moss communities of Chopta-Tunganath in the Garhwal Himalaya. Journal of the Bombay Natural History Society 99 (3): 418–433.
[OZB-O03] Ochyra, R., J. Żarnowiec & H. Bednarek-Ochyra. 2003. Census Catalogue of Polish Mosses. Institute of Botany, Polish Academy of Sciences: Cracow.
[S04] Smith, A. J. E. 2004. The Moss Flora of Britain and Ireland 2nd ed. Cambridge University Press.
[SK02] Streimann, H., & N. Klazenga. 2002. Catalogue of Australian Mosses. Flora of Australia Supplementary Series 17. Australian Biological Resources Study: Canberra.
[VH02] Vanderpoorten, A., L. Hedenäs, C. J. Cox & A. J. Shaw. 2002. Phylogeny and morphological evolution of the Amblystegiaceae (Bryopsida). Molecular Phylogenetics and Evolution 23 (1): 1–21.