As violas ou violetas son plantas herbáceas do xénero Viola, da familia das violáceas con talos rastreiros, follas radicais con pecíolos longos ou curtos, ásperas e en forma de corazón, lanceoladas, ovais, con forma de ril, setadas etc. cos bordos festonados, lisos ou dentados. Producen flores miúdas de cor azul intensa, morada clara, violeta, púrpura, branca ou amarela, de talo longo e magro. Algunhas posúen un suave recendo moi apreciado en perfumaría, son famosas as violas da rexión de Tolosa en Francia e algunhas especies medran bravas en GalizaJuan Cuveiro Piñol (1876): Diccionario Gallego, Barcelona. Empréganse coma plantas ornamentais en vasos e xardíns. Recoñécense coma sinal da modestia por mor a que as súas floriñas semellan agocharse timidamente baixo as súas follas grandes e en forma de corazón.
En Galiza aparecen algunhas especies bravas como: Viola riviniana, viola brava, a especie máis común das carballeiras, claros de bosque e prados húmidos e sombrizos de toda GalizaMini Atlas Xeobotánico de Galicia - http://www.vexetaciondegalicia.es/plantas.php?id=viola . Viola tricolor, herba da trindadeMarcial Valladares Núñez (1884): Diccionario gallego-castellano, Santiago, Imp. Seminario Conciliar - http://sli.uvigo.es/DdD/ddd_pescuda.php?pescuda=trinid%E1&tipo_busca=lema, da que sae a coñecida ornamental Viola x wittrockiana (pensamento). Viola odorata, viola de cheiro. Viola palustris, viola de braña. Viola canina, viola de canJuan Cuveiro Piñol (1876): Diccionario Gallego, Barcelona - http://sli.uvigo.es/DdD/ddd_pescuda.php?pescuda=viola&tipo_busca=lema.
Especies Viola abyssinica Steud. ex Oliv. Viola acanthophylla Leyb. ex Reiche Viola accrescens Klokov Viola acuminata Ledeb Viola adenothrix Hayata Viola adriatica Freyn Viola adunca Sm. Viola aetnensis Parl. Viola aetolica Boissieu H. & Heldr. Viola affinis Le Conte Viola agellae Pollard C. L. Viola aizoon Reiche Viola alaica Vved. Viola alba Besser, violeta branca. Viola alexandrowiana (W.Becker) Juz. Viola alexejana Kamelin & Junussov Viola allchariensis Beck G. Viola alliariaefolia Nakai Viola allochroa Botsch. Viola alpina Jacq. Viola altaica Ker Gawl. Viola amamiana Hatusima Viola ambigua Waldst.& Kit Viola amurica W. Becker Viola anagae Gilli Viola angustifolia Phil. Viola angustipulata Chang Viola appalachiensis L.K.Henry Viola araucaniae W.Becker Viola arborescens L. Viola argenteria Moraldo & G.Forneris Viola argentina W.Becker Viola arguta Willd. ex Roem. & Schult. Viola arsenica Beck Viola arvensis Murray, violeta dos prados. Viola asterias Hook & Arn. Viola athois W.Becker Viola atropurpurea Leyb. Viola aurantiaca Leyb. Viola aurata Phil. Viola aurea Kellogg Viola auricolor Skottsb. Viola auricula Leyb. Viola avatschensis Becker W & Hulten A Viola awagatakensis Yamazaki T. Viola bakeri Greene E. L. Viola bambusetorum Hand.-Mazz. Viola bangiana W.Becker Viola bangii Rusby Viola banksii K.R.Thiele & Prober - (Australia) Viola barroetana W.Schaffn. Viola battandieri W.Becker Viola beamani Calderón Viola beckiana Fiala Viola beckwithii Torr. & Gray Viola bernardii (Greene) Greene Viola bertolonii Pio Viola betonicifolia Sm. Viola bezdelevae Vorosch. Viola bhutanica Hara Viola bicolor Pursh Viola biflora L. Viola biflora Regel Viola binayensis Okamoto & Ueda K. Viola bissellii House H. D. Viola bissetii Maxim Viola blanda Willd. Viola blandaeformis Nakai Viola bocquetiana Yildirimli Viola boissieuana Makino Viola bornmuelleri Erben M.]] Viola brachyceras Turcz. Viola brachypetala Gay Viola brachyphylla W. Becker Viola brevistipulata [Franch & Savat.](W. Becker) Kitag Viola brevistipulata (Franch. & Sav) W. Becker Viola bridgesii Britton N. L. Viola brittoniana Pollard C. L. Viola bubanii Timb. & Lagr. Viola buchtienii Gand. Viola bulbosa Maxim Viola bustillosia Gay Viola calaminaria Lej. A Viola calcarata L. Viola calchaquiensis W. Becker Viola calderensis W. Becker Viola caleyana Don D. A. Viola californica Baker M. S. Viola californica Greene Viola cameleo Boissieu H. Viola canadensis L. Viola canescens Wallich Viola canina L., viola de can. Viola canobarbata Leyb. Viola capillaris Pers. Viola castillonii (W. Becker) Xifreda & Sanso Viola catalonica W. Becker Viola caucasica Kolen. Viola cazorlensis Gand. Viola cenisia L. Viola cerasifolia St.Hilaire Viola chaerophylloides (Regel) W. Becker Viola chamaedrys Leyb. Viola chamissoniana Gingins Viola charlestonensis Baker M. S. & Clausen J. C. Viola charlestownensis Baker M. S. & Clausen J. C. Viola chassanica Korkischko R.I. Viola cheiranthifolia Humb., Bonpl. & Kunth., violeta do Teide Viola chelmea Boiss. & Heldr. Viola chiapasiensis W.Becker Viola chrysantha Phil. Viola ciliata Schltdl. Viola cinerea Boiss. Viola clauseniana Baker M. S. Viola cleistogamoides (Adams L.) Seppelt R.D. Viola cochranei Ballard H. E. Viola collina Besser. Viola columnaris Skottsberg Viola commersonii De Candolle ex Gingins]] Viola commutata Waisb. Viola comollia Massara Viola concordifolia Ching J. Wang Viola confertifolia Chang Viola confusa Champ. ex Benth]] Viola conjugens Greene E. L. Viola consobrina House H. D. Viola conspersa Reichenb. Viola contempta Jordan A Viola cordifolia (Nuttall) Schweinitz Viola cornuta L. Viola coronifera W. Becker Viola corralensis Phil. Viola corsica Nyman Viola cotyledon Gingins Viola crassa Makino Viola crassicalcarata Ching J. Wang Viola crassifolia Fenzl. Viola crassiuscula Bory - Violeta de Serra Nevada Viola cretacea Klokov Viola cretica Boiss.& Heldr. Viola cuatrecasasii L.B.Smith & A.Fernández Viola cucullata Aiton Viola cuicochensis Hieron. Viola cummingii W. Becker Viola cuneata Watson S. Viola cunninghamii Hook J.D. Viola curicoensis Becker G. Viola curvistylis Boissieu H. & Captin. Viola cuspidifolia W. Becker Viola cyathiformis W. Becker Viola dacica Borbás Viola dactyloides Roemer R & Schultes J.A. Viola dasyphylla W. Becker Viola davidii Franch. Viola decipiens Reiche Viola declinata Waldst. & Kit. Viola decumbens Gmel. J.F. Viola delavayi Franch. Viola delphinantha Boiss. Viola demetria Prolongo ex Boiss. Viola diamantiaca Nakai Viola dichroa Boissieu H. & Huet A. Viola diffusa Gingins Viola diffusoides Ching J. Wang Viola dimorphophyllaY. S. Chen & Q. E. Yang Viola dirimliensisBlaxland Viola dirphya Tiniakov A. Viola disjuncta W. Becker Viola dissecta ' Viola diversifolia (De Candolle) W. Becker Viola doerfleri Degen Viola doii Takenouchi Viola dolichocentra Botsch. Viola dolichoceras Ching J. Wang Viola dombeyana De Candolle Viola domeikoana Gay C. Viola domingensis Urb. Viola donetzkiensis Klokov M.V. Viola douglasii Steud. Viola dubyana Burnat [Gremli] Viola dukadjinica W. Becker & Kosanin Viola dyris Maire R. Viola eamesii House H. D. Viola ecuadorensis W. Becker Viola eizanensis (Makino) Makino Viola elatior Fries]] Viola elegantula Schott. Viola elisabethae Klokov Viola emeiensis Ching J. Wang Viola eminii (Engl.) Fries R.E. Viola epipsila Ledeb.]] Viola epipsiloides Love A. & D. Viola ermenekensisYild. & Dinc Viola etrusca Erben M. Viola eugeniae Parlatore Viola evae Hieron. ex W. Becker Viola exigua W. Becker Viola eximia Formánek Viola fargesii Boissieu H. Viola faurieana W. Becker Viola feldtschenkoana W. Becker Viola filicaulis Hook F. Viola filicetorum Greene E. L. Viola fimbriatula Sm. Viola fischeri W. Becker Viola fissifolia Kitagawa Viola flagelliformis Hemsley W. B. Viola flettii Piper C. V. Viola florairiensis Correvon Viola flos-evae Hieron. Viola fluehmannii Phil. Viola formosana Hayata Viola formosana Hayata Viola formosana Hsieh C.F. Viola forrestiana W. Becker Viola fragrans Sieber Viola frank-smithii Holmgren N. H. Viola friderici G. Viola frigida Phil. Viola frondosa (Velen.) Hayek Viola fruticosa W. Becker Viola fuscifolia W. Becker Viola fuscoviolacea (Adams L.G.) James T.A. Viola germaninii Sparre Viola glabella Nuttall T. Viola glacialis Poepp. & Endl. Viola glandularis Ballard H. E. & Jorg P. Viola glandulifera Hook Viola glausescens Oudem. Viola glechomoides Leyb. Viola gmeliniana Roemer R & Schultes J.A. Viola godoyae Phil. Viola gracilis Sibth.& Sm. Viola gracillima St.Hilaire A. Viola graeca ( Becker G.) Halacsy Viola grahami Bentham G. Viola grandisepala W. Becker Viola granulosa Wedd. Viola grayi Franch. & Sav. Viola greenmani House H. D. Viola grisebachiana Boiss. Viola grisebachiana Vis. Viola grypoceras Gray A. Viola guadalupensis Powell A. & Wauer B. Viola guatemalensis W. Becker Viola guineensis Schumach. & Thonn. Viola hallii Gray A. Viola hamiltoniana Don D. Viola hancockii W. Becker Viola hastata Michx. Viola hederacea Labil.]] - (Australia). Viola hediniana W. Becker Viola heldreichiana Boiss. Viola helena C.N.Forbes & Lydgate Viola helenae C.N.Forbes & Lydgate Viola hemsleyana Calderón Viola henryi Boiss. Viola hieronymi W.Becker Viola hillii W.Becker Viola himalayensis W.Becker Viola hirsutula Brainerd Viola hirta L. Viola hirtipes Moore S. Viola hispida Lam. Viola hissarica Juz. Viola hollickii House H. D. Viola hondoensis W.Becker & Boiss. Viola hookeri Thomson ex Hook Viola hookeriana Kunth. Viola hosakae H.St.John Viola hossei W.Becker Viola howellii Gray A. Viola huesoensis Martic. Viola huidobrii Gay Viola hultenii W.Becker Viola humilis Kunth. Viola hunanensis Hand.-Mazz. Viola hymettia Boiss. & Heldr. Viola ibukiana Makino Viola ignobilis Rupr. Viola improcera L.G.Adams Viola incisa Turcz. Viola inconspicua Blume Viola indica W.Becker Viola ircutiana Turcz Viola irinae Zolot. Viola isaurica Contandr. & Quezel Viola ishidoyana Nakai H. Viola isopetala Juz. Viola iwagawai Makino Viola jagellonica Zapal. Viola jalapaensis W. Becker Viola jangiensis W. Becker Viola japonica Langsd.ex Ging. Viola jaubertiana Mares & Virgineix Viola javanica W. Becker Viola joergensenii W. Becker Viola johnstonii W. Becker Viola jooi Janka Viola jordanii Henry J.K. Viola kalbreyeri W. Becker Viola kamibayashii Nakai H. Viola kapsanensis Nakai H. Viola kashmiriana W. Becker Viola kauaensis Gray A. Viola keiskei Janka Viola keiskei Miq. Viola kermesina W. Becker Viola kiangsiensis W. Becker Viola kitaibeliana Roem. & Schultes J. A. Viola kitamiana Nakai Viola kizildaghensis Dinç & Yldirimli Viola kjellbergii Melchior H. Viola koraiensis Nakai Viola kosanensis Hayata Viola kosaninii Hayek Viola kunawarensis Royle Viola kupcokiana W. Becker Viola kupfferi Klokov Viola kusanoana Makino Viola kusnezowiana W. Becker Viola labradorica Schrank Viola lactea Sm. Viola lactiflora Nakai Viola lanaiensis W. Becker Viola lanceifolia Schumach. & Thonn. Viola lanceolata L. Viola langeana Valentine Viola langsdorfii (Regel) Fisch.ex Gingins Viola lanifera Becker G. Viola latistipulata Hemsley W. B. Viola lavrenkoana Klokov Viola lehmannii W. Becker Viola leyboldiana Phil. Viola lianhuashanensis Ching J. Wang & Sun K. Viola libanotica Boiss. Viola lilloana W.Becker Viola linifolia Poir. Viola lithion Holmgren N. H. & Holmgren P. K. Viola littoralis Sprengel Viola llullaillacoensis W. Becker Viola lobata Benth Viola lovelliana Brainerd Viola lucens W. Becker Viola luciae Skottsberg Viola lutea Hudson Viola lyallii Hook F. Viola macloskeyi Lloyd F. E. Viola macroceras Bunge Viola maculata Cav. Viola maculata Cav. & Weibel Viola magellanica Forster F. Viola magellensis Porta & Rigo ex Strobl. Viola magnifica Wang ex Wang X.D. Viola maichurensis Pissjaukova Viola makranica Omer S. & Qaiser M. Viola malteana House H. D. Viola mandonii W.Becker Viola mandschurica W.Becker Viola maroccana Maire Viola mauritii Tepl. Viola maviensis Viola maximowicziana Makino Viola maymanica Grey-Wilson Viola mearnsii Merrill Viola membranacea W. Becker