Calamagrostis (reed grass or smallweed) is a genus of flowering plants in the grass family Poaceae, with about 260 species that occur mainly in temperate regions of the globe. Towards equatorial latitudes, species of Calamagrostis generally occur at higher elevations. These tufted perennials usually have hairless narrow leaves. The ligules are usually blunt. The inflorescence forms a panicle. Some may be reed-like.

The plants may be rhizomatous (underground stems with shoots), stoloniferous (with runners), or caespitose (growing in tufts or clumps). The bisexual spikelets have a single floret and generally they are purple or purple-brown. The spikelets are clustered into inflorescences, which usually develop in early- to mid-summer on long culms ( = stems).

Many species of Calamagrostis are morphologically similar, but they generally occur in distinct habitats, and they have unique geographical distributions. Given the subtle distinctions between many closely related taxa, there are several species complexes that could benefit from additional systematic study. Even the generic boundaries of the genus are controversial. For example, species in the genus Deyeuxia (named after French chemist Nicolas Deyeux), distributed largely in the southern hemisphere are morphologically very similar to species of Calamagrostis. It may be appropriate to recognize all of these species in a single genus, but this will require detailed scientific study of DNA of species from around the world.

Some Calamagrostis can be very decorative, and are widely cultivated largely in northern temperate zones. The species Calamagrostis brachytricha and the cultivar Calamagrostis × acutiflora 'Karl Foerster' are recipients of the Royal Horticultural Society's Award of Garden Merit.

The word "Calamagrostis" is derived from the Greek word kalamos (reed) and agrostis (a kind of grass).

Species

Calamagrostis contains the following recognised species:

  • Calamagrostis abnormis <small>(Hook.f.) U.Shukla</small>
  • Calamagrostis acuminata <small>(Vickery) Govaerts</small>
  • Calamagrostis × acutiflora <small>(Schrad.) DC.</small>
  • Calamagrostis affinis <small>(M.Gray) Govaerts</small>
  • Calamagrostis ajanensis <small>Kharkev. & Prob.</small>
  • Calamagrostis alajica <small>Litv.</small>
  • Calamagrostis alba <small>(J.Presl) Steud.</small>
  • Calamagrostis albiflora <small>Vaniot</small>
  • Calamagrostis altaica <small>Tzvelev</small>
  • Calamagrostis amoena <small>(Pilg.) Pilg.</small>
  • Calamagrostis ampliflora <small>Tovar</small>
  • Calamagrostis × andrejewii <small>Litv.</small>
  • Calamagrostis angustifolia <small>Kom.</small>
  • Calamagrostis anthoxanthoides <small>(Munro) Regel</small>
  • Calamagrostis appressa <small>(Vickery) Govaerts</small>
  • Calamagrostis archboldii <small>Hitchc.</small>
  • Calamagrostis arundinacea <small>(L.) Roth</small>
  • Calamagrostis atjehensis <small>Ohwi</small>
  • Calamagrostis aurea <small>(Munro) Hack. ex Sodiro</small>
  • Calamagrostis australis <small>(Moritzi) Buse</small>
  • Calamagrostis austrodensa <small>Govaerts</small>
  • Calamagrostis austroscaberula <small>Govaerts</small>
  • Calamagrostis autumnalis <small>Koidz.</small>
  • Calamagrostis avenoides <small>(Hook.f.) Cockayne</small>
  • Calamagrostis × badzhalensis <small>Prob.</small>
  • Calamagrostis baicalensis <small>(Litv.) Steph. ex Komarov</small>
  • Calamagrostis balkharica <small>P.A.Smirn.</small>
  • Calamagrostis benthamiana <small>(Vickery) Govaerts</small>
  • Calamagrostis × bihariensis <small>Simonk.</small>
  • Calamagrostis bogotensis <small>(Pilg.) Pilg.</small>
  • Calamagrostis bolanderi <small>Thurb.</small>
  • Calamagrostis boliviensis <small>Hack.</small>
  • Calamagrostis borii <small>Tzvelev</small>
  • Calamagrostis boyacensis <small>Swallen & Garc.-Barr.</small>
  • Calamagrostis brachyathera <small>(Stapf) Govaerts</small>
  • Calamagrostis brassii <small>Hitchc.</small>
  • Calamagrostis breviaristata <small>(Wedd.) Pilg.</small>
  • Calamagrostis brevifolia <small>(J.Presl) Steud.</small>
  • Calamagrostis breweri <small>Thurb.</small>
  • Calamagrostis cabrerae <small>Parodi</small>
  • Calamagrostis cainii <small>Hitchc.</small>
  • Calamagrostis calderillensis <small>Pilg.</small>
  • Calamagrostis canadensis <small>(Michx.) P.Beauv.</small>
  • Calamagrostis canescens <small>(Weber) Roth</small>
  • Calamagrostis carchiensis <small>Laegaard</small>
  • Calamagrostis carinata <small>(Vickery) Govaerts</small>
  • Calamagrostis caucasica <small>Trin.</small>
  • Calamagrostis cephalantha <small>Pilg.</small>
  • Calamagrostis chalybaea <small>(Laest.) Fr.</small>
  • Calamagrostis chaseae <small>Luces</small>
  • Calamagrostis chilensis <small>Phil.</small>
  • Calamagrostis chrysantha <small>(J.Presl) Steud.</small>
  • Calamagrostis chrysophylla <small>(Phil.) Govaerts</small>
  • Calamagrostis cleefii <small>Escalona</small>
  • Calamagrostis clipeata <small>Vaniot</small>
  • Calamagrostis coahuilensis <small>P.M.Peterson, Soreng & Valde's-Reyna</small>
  • Calamagrostis coarctata <small>Eaton</small>
  • Calamagrostis conferta <small>(Keng) P.C.Kuo & S.L.Lu</small>
  • Calamagrostis × conwentzii <small>Ulbr.</small>
  • Calamagrostis cordechii <small>Govaerts</small>
  • Calamagrostis crassiuscula <small>(Vickery) Govaerts</small>
  • Calamagrostis crispa <small>(Rugolo & Villav.) Govaerts</small>
  • Calamagrostis cryptolopha <small>(Wedd.) Hitchc.</small>
  • Calamagrostis curta <small>(Wedd.) Hitchc.</small>
  • Calamagrostis curtoides <small>(Rugolo & Villav.) Govaerts</small>
  • Calamagrostis curvula <small>(Wedd.) Pilg.</small>
  • Calamagrostis cuzcoensis <small>Tovar</small>
  • Calamagrostis × czerepanovii <small>Husseinov</small>
  • Calamagrostis debilis <small>Hook.f.</small>
  • Calamagrostis decipiens <small>(R.Br.) Govaerts</small>
  • Calamagrostis decora <small>Hook.f.</small>
  • Calamagrostis densiflora <small>(J.Presl) Steud.</small>
  • Calamagrostis deschampsiiformis <small>C.E.Hubb.</small>
  • Calamagrostis deschampsioides <small>Trin.</small>
  • Calamagrostis deserticola <small>(Phil.) Phil.</small>
  • Calamagrostis diemii <small>(Rúgolo) Soreng</small>
  • Calamagrostis diffusa <small>(Keng) Keng f.</small>
  • Calamagrostis distantifolia <small>Luchnik</small>
  • Calamagrostis divaricata <small>P.M.Peterson & Soreng</small>
  • Calamagrostis divergens <small>Swallen</small>
  • Calamagrostis dmitrievae <small>Tzvelev</small>
  • Calamagrostis drummondii <small>(Steud.) Govaerts</small>
  • Calamagrostis effusiflora <small>(Rendle) P.C.Kuo & S.L.Lu ex J.L.Yang</small>
  • Calamagrostis elatior <small>(Griseb.) A.Camus</small>
  • Calamagrostis eminens <small>(J.Presl) Steud.</small>
  • Calamagrostis emodensis <small>Griseb.</small>
  • Calamagrostis epigejos <small>(L.) Roth</small>
  • Calamagrostis erectifolia <small>Hitchc.</small>
  • Calamagrostis eriantha <small>(Kunth) Steud.</small>
  • Calamagrostis expansa <small>(Munro ex Hillebr.) Hitchc.</small>
  • Calamagrostis fauriei <small>Hack.</small>
  • Calamagrostis fibrovaginata <small>Laegaard</small>
  • Calamagrostis fiebrigii <small>Pilg.</small>
  • Calamagrostis filifolia <small>Merr.</small>
  • Calamagrostis filipes <small>(Keng) P.C.Kuo & S.L.Lu ex J.L.Yang</small>
  • Calamagrostis flaccida <small>Keng f.</small>
  • Calamagrostis foliosa <small>Kearney</small>
  • Calamagrostis frigida <small>(Benth.) Maiden & Betche</small>
  • Calamagrostis fulgida <small>Laegaard</small>
  • Calamagrostis fulva <small>(Griseb.) Kuntze</small>
  • Calamagrostis fuscata <small>(J.Presl) Steud.</small>
  • Calamagrostis gayana <small>(Steud.) Soreng</small>
  • Calamagrostis gigas <small>Takeda</small>
  • Calamagrostis glacialis <small>(Wedd.) Hitchc.</small>
  • Calamagrostis griffithii <small>(Bor) G.Singh</small>
  • Calamagrostis guamanensis <small>Escalona</small>
  • Calamagrostis guatemalensis <small>Hitchc.</small>
  • Calamagrostis gunniana <small>(Nees) Reeder</small>
  • Calamagrostis hackelii <small>Lillo ex Stuck.</small>
  • Calamagrostis hakonensis <small>Franch. & Sav.</small>
  • Calamagrostis × hartmaniana <small>Fr.</small>
  • Calamagrostis × haussknechtiana <small>Torges</small>
  • Calamagrostis hedbergii <small>Melderis</small>
  • Calamagrostis henryi <small>(Rendle) P.C.Kuo & S.L.Lu ex J.L.Yang</small>
  • Calamagrostis heterophylla <small>(Wedd.) Pilg.</small>
  • Calamagrostis hieronymi <small>Hack.</small>
  • Calamagrostis hillebrandii <small>(Munro ex Hillebr.) C.L.Hitchc.</small>
  • Calamagrostis hirta <small>(Sodiro ex Mille) Laegaard</small>
  • Calamagrostis holciformis <small>Jaub. & Spach</small>
  • Calamagrostis holmii <small>Lange</small>
  • Calamagrostis howellii <small>Vasey</small>
  • Calamagrostis hupehensis <small>(Rendle) Chase</small>
  • Calamagrostis imbricata <small>(Vickery) Govaerts</small>
  • Calamagrostis inaequalis <small>(Vickery) Govaerts</small>
  • Calamagrostis inexpansa <small>A.Gray</small>
  • Calamagrostis insperata <small>Swallen</small>
  • Calamagrostis intermedia <small>(J.Presl) Steud.</small>
  • Calamagrostis involuta <small>Swallen</small>
  • Calamagrostis jamesonii <small>Steud.</small>
  • Calamagrostis kalarica <small>Tzvelev</small>
  • Calamagrostis kengii <small>T.F.Wang</small>
  • Calamagrostis killipii <small>Swallen</small>
  • Calamagrostis koelerioides <small>Vasey</small>
  • Calamagrostis kokonorica <small>Keng ex Tzvelev</small>
  • Calamagrostis korotkyi <small>Litv.</small>
  • Calamagrostis korshinskyi <small>Litv.</small>
  • Calamagrostis × kotulae <small>Zapal.</small>
  • Calamagrostis × kuznetzovii <small>Tzvelev</small>
  • Calamagrostis lahulensis <small>G.Singh</small>
  • Calamagrostis lapponica <small>(Wahlenb.) Hartm.</small>
  • Calamagrostis lawrencei <small>(Vickery) Govaerts</small>
  • Calamagrostis leiophylla <small>(Wedd.) Hitchc.</small>
  • Calamagrostis leonardii <small>Chase</small>
  • Calamagrostis levipes <small>(Keng) P.C.Kuo & S.L.Lu ex J.L.Yang</small>
  • Calamagrostis licentiana <small>Hand.-Mazz.</small>
  • Calamagrostis ligulata <small>(Kunth) Hitchc.</small>
  • Calamagrostis linifolia <small>Govaerts</small>
  • Calamagrostis llanganatensis <small>Laegaard</small>
  • Calamagrostis longiseta <small>Hack.</small>
  • Calamagrostis macbridei <small>Tovar</small>
  • Calamagrostis macilenta <small>(Griseb.) Litv.</small>
  • Calamagrostis macrophylla <small>(Pilg.) Pilg.</small>
  • Calamagrostis malamalensis <small>Hack. ex Stuck.</small>
  • Calamagrostis mandoniana <small>(Wedd.) Pilg.</small>
  • Calamagrostis matsumurae <small>Maxim.</small>
  • Calamagrostis mckiei <small>(Vickery) Govaerts</small>
  • Calamagrostis menhoferi <small>Govaerts</small>
  • Calamagrostis mesathera <small>(Vickery) Govaerts</small>
  • Calamagrostis microseta <small>(Vickery) Govaerts</small>
  • Calamagrostis minarovii <small>Hüseyin</small>
  • Calamagrostis minima <small>(Pilg.) Tovar</small>
  • Calamagrostis minor <small>(Benth.) J.M.Black</small>
  • Calamagrostis mollis <small>Pilg.</small>
  • Calamagrostis montanensis <small>(Scribn.) Scribn. ex Vasey</small>
  • Calamagrostis moupinensis <small>Franch.</small>
  • Calamagrostis muiriana <small>B.L.Wilson & Sami Gray</small>
  • Calamagrostis mulleri <small>Luces</small>
  • Calamagrostis munroi <small>Boiss.</small>
  • Calamagrostis nagarum <small>(Bor) G.Singh</small>
  • Calamagrostis nardifolia <small>(Griseb.) Hack. ex Stuck.</small>
  • Calamagrostis neesii <small>Steud.</small>
  • Calamagrostis neocontracta <small>Govaerts</small>
  • Calamagrostis niitakayamensis <small>Honda</small>
  • Calamagrostis ningxiaensis <small>D.Z.Ma & J.N.Li</small>
  • Calamagrostis nitidula <small>Pilg.</small>
  • Calamagrostis nivicola <small>(Hook.f.) Hand.-Mazz.</small>
  • Calamagrostis nudiflora <small>(Vickery) Govaerts</small>
  • Calamagrostis nutkaensis <small>(J.Presl) Steud.</small>
  • Calamagrostis obtusata <small>Trin.</small>
  • Calamagrostis ophitidis <small>(Howell) Nygren</small>
  • Calamagrostis orbignyana <small>(Wedd.) Pilg.</small>
  • Calamagrostis orizabae <small>(Rupr. ex E.Fourn.) Beal</small>
  • Calamagrostis ovata <small>(J.Presl) Steud.</small>
  • Calamagrostis × paradoxa <small>Lipsky</small>
  • Calamagrostis parsana <small>(Bor) M.Dogan</small>
  • Calamagrostis parviseta <small>(Vickery) Reeder</small>
  • Calamagrostis patagonica <small>(Speg.) Makloskie</small>
  • Calamagrostis pavlovii <small>(Roshev.) Roshev.</small>
  • Calamagrostis perplexa <small>Scribn.</small>
  • Calamagrostis petelotii <small>(Hitchc.) Govaerts</small>
  • Calamagrostis pickeringii <small>A.Gray</small>
  • Calamagrostis pinetorum <small>Swallen</small>
  • Calamagrostis pisinna <small>Swallen</small>
  • Calamagrostis pittieri <small>Hack.</small>
  • Calamagrostis planifolia <small>(Kunth) Trin. ex Steud.</small>
  • Calamagrostis poluninii <small>T.J.Sørensen</small>
  • Calamagrostis polycephala <small>Vaniot</small>
  • Calamagrostis polygama <small>(Griseb.) Parodi</small>
  • Calamagrostis × ponojensis <small>Montell</small>
  • Calamagrostis porteri <small>A.Gray</small>
  • Calamagrostis × prahliana <small>Torges</small>
  • Calamagrostis preslii <small>(Kunth) Hitchc.</small>
  • Calamagrostis pringlei <small>Beal</small>
  • Calamagrostis przevalskyi <small>Tzvelev</small>
  • Calamagrostis × pseudodeschampsioides <small>Tzvelev</small>
  • Calamagrostis pseudophragmites <small>(Haller f.) Koeler</small>
  • Calamagrostis pungens <small>Tovar</small>
  • Calamagrostis purpurascens <small>R.Br.</small>
  • Calamagrostis purpurea <small>(Trin.) Trin.</small>
  • Calamagrostis pusilla <small>Reeder</small>
  • Calamagrostis quadriseta <small>(Labill.) Spreng.</small>
  • Calamagrostis radicans <small>Vaniot</small>
  • Calamagrostis ramonae <small>Escalona</small>
  • Calamagrostis rauhii <small>Tovar</small>
  • Calamagrostis recta <small>(Kunth) Trin. ex Steud.</small>
  • Calamagrostis reflexa <small>(Vickery) Govaerts</small>
  • Calamagrostis reitzii <small>Swallen</small>
  • Calamagrostis × rigens <small>Lindgr.</small>
  • Calamagrostis rigescens <small>(J.Presl) Scribn.</small>
  • Calamagrostis rigida <small>(Kunth) Trin. ex Steud.</small>
  • Calamagrostis rodwayi <small>(Vickery) Govaerts</small>
  • Calamagrostis rosea <small>(Griseb.) Hack.</small>
  • Calamagrostis rubescens <small>Buckley</small>
  • Calamagrostis rupestris <small>Trin.</small>
  • Calamagrostis sachalinensis <small>F.Schmidt</small>
  • Calamagrostis sajanensis <small>Malyschev</small>
  • Calamagrostis salina <small>Tzvelev</small>
  • Calamagrostis scaberula <small>Swallen</small>
  • Calamagrostis scabrescens <small>Griseb.</small>
  • Calamagrostis scabriflora <small>Swallen</small>
  • Calamagrostis sclerantha <small>Hack.</small>
  • Calamagrostis sclerophylla <small>(Stapf) Hitchc.</small>
  • Calamagrostis scopulorum <small>M.E.Jones</small>
  • Calamagrostis scotica <small>(Druce) Druce</small>
  • Calamagrostis sesquiflora <small>(Trin.) Tzvelev</small>
  • Calamagrostis setiflora <small>(Wedd.) Pilg.</small>
  • Calamagrostis sichuanensis <small>J.L.Yang</small>
  • Calamagrostis sikangensis <small>(Keng) P.C.Kuo & S.L.Lu ex J.L.Yang</small>
  • Calamagrostis sinelatior <small>(Keng) P.C.Kuo & S.L.Lu ex J.L.Yang</small>
  • Calamagrostis smirnowii <small>Litv. ex Petrov</small>
  • Calamagrostis spicigera <small>(J.Presl) Steud.</small>
  • Calamagrostis spruceana <small>(Wedd.) Hack. ex Sodiro</small>
  • Calamagrostis srilankensis <small>Davidse</small>
  • Calamagrostis staintonii <small>G.Singh</small>
  • Calamagrostis stenophylla <small>Hand.-Mazz.</small>
  • Calamagrostis steyermarkii <small>Swallen</small>
  • Calamagrostis stolizkai <small>Hook.f.</small>
  • Calamagrostis stricta <small>(Timm) Koeler</small>
  • Calamagrostis × strigosa <small>(Wahlenb.) Hartm.</small>
  • Calamagrostis subacrochaeta <small>Nakai</small>
  • Calamagrostis × subchalybaea <small>Tzvelev</small>
  • Calamagrostis × subepigeios <small>Tzvelev</small>
  • Calamagrostis sublanceolata <small>Honda</small>
  • Calamagrostis × submonticola <small>Prob.</small>
  • Calamagrostis × subneglecta <small>Tzvelev</small>
  • Calamagrostis suka <small>Speg.</small>
  • Calamagrostis tacomensis <small>K.L.Marr & Hebda</small>
  • Calamagrostis tarmensis <small>Pilg.</small>
  • Calamagrostis tashiroi <small>Ohwi</small>
  • Calamagrostis × tatianae <small>Prob.</small>
  • Calamagrostis teberdensis <small>Litv.</small>
  • Calamagrostis teretifolia <small>Laegaard</small>
  • Calamagrostis tianschanica <small>Rupr.</small>
  • Calamagrostis tibetica <small>(Bor) Tzvelev</small>
  • Calamagrostis tolucensis <small>(Kunth) Trin. ex Steud.</small>
  • Calamagrostis × torgesiana <small>Hausskn.</small>
  • Calamagrostis trichodonta <small>(Wedd.) Soreng</small>
  • Calamagrostis turkestanica <small>Hack.</small>
  • Calamagrostis tweedyi <small>(Scribn.) Scribn.</small>
  • Calamagrostis tzvelevii <small>Hüseyin</small>
  • Calamagrostis × uralensis <small>Litv.</small>
  • Calamagrostis × ussuriensis <small>Tzvelev</small>
  • Calamagrostis valida <small>Sohns</small>
  • Calamagrostis varia <small>(Schrad.) Host</small>
  • Calamagrostis × vassiljevii <small>Tzvelev</small>
  • Calamagrostis velutina <small>(Nees & Meyen) Steud.</small>
  • Calamagrostis veresczaginii <small>Zolot.</small>
  • Calamagrostis vicunarum <small>(Wedd.) Pilg.</small>
  • Calamagrostis villosa <small>(Chaix) J.F.Gmel.</small>
  • Calamagrostis × vilnensis <small>Besser</small>
  • Calamagrostis violacea <small>(Wedd.) Hack.</small>
  • Calamagrostis viridiflavescens <small>(Poir.) Steud.</small>
  • Calamagrostis viridis <small>(Phil.) Soreng</small>
  • Calamagrostis vulcanica <small>Swallen</small>
  • Calamagrostis yanyuanensis <small>J.L.Yang</small>
  • Calamagrostis × yatabei <small>Maxim.</small>
  • Calamagrostis youngii <small>(Hook.f.) Buchanan</small>
  • Calamagrostis zenkeri <small>(Trin.) Davidse</small>
  • Calamagrostis × zerninensis <small>Lüderw.</small>

Formerly placed here

  • Laegaardia ecuadoriense (as Calamagrostis ecuadoriensis <small>Laegaard</small>)
  • Paramochloa crispifolia (as Calamagrostis crispifolius )
  • Paramochloa effusa (as Calamagrostis effusa <small>(Kunth) Steud.</small>, C. areantha , or C. funckii )

References

  • Grass Genera of the World
  • Interactive Key to Calamagrostis of North America