Viola L.

1. Viola L. View in CoL 2

Leaves petiolate. Sepals prolonged into short appendages below the point of their insertion. Corolla zygomorphic, the lower petal spurred. Connectives of stamens with an apical appendage; the 2 lower stamens spurred. Style thickened above; stigma of various shapes (beaked, bilobed, capitate). Seeds with an elaiosome.

Various species and hybrids of the genus are commonly cultivated, especially the sweet violet, 1, and the garden pansy, V. x wittrockiana Gams (= V. hortensis auct.). The origin of the latter is not known with certainty, but it is thought to have arisen from hybrids between 74, 78 and V. altaica Ker-Gawler. Amongst other European species in cultivation are 48, 63, 73, 74 and their hybrids.

Description of flowers in the text refer to open (chasmogamous) flowers. Cleistogamous flowers are produced by species 1-33 and by 88-89. Flower lengths are measured from apex of spur to apex of lower petal, or from apex of upper to apex of lower petal, whichever is the longer. The term rosulate is used for plants with a loose, basal rosette of 3-5 petiolate leaves from the axils of which arise flowering branches, and the term arosulate for plants in which this basal rosette is lacking.

Literature: W. Becker, Violae Europaeae . Dresden. 1910. (Originally published in Beih. Bot. Centr. 26(2): 1 -44 (1909); 289-390 (1910).) 1 Aerial stems woody, at least below 2 Spur less than 10 mm 3 Flowers 2-2-5 cm, purple-violet 60. allchariensis 3 Flowers 1 -1-5 cm, whitish, pale violet or yellow 4 Leaves ovate to linear-lanceolate; petals whitish or pale violet 88. arborescens 4 Leaves obovate; petals yellow 89. scorpiuroides 2 Spur more than 10 mm 5 Spur c. 12 mm 91. kosaninii 5 Spur more than 16 mm 6 Spur 16-18 mm; lower petal entire 90. delphinantha 6 Spur 20-30 mm; lower petal emarginate 92. cazorlensis 1 Aerial stems herbaceous or absent 7 Lateralpetalsdirecteddownwards; styleusuallyneither capitate nor bilobed 8 Style capitate; rhizome thick and fleshy 32. obliqua 8 Style not capitate; rhizome not thick or fleshy 9 Caulescent, with leafy, aerial flowering stems 10 Plant lacking basal leaf-rosette; leaves usually longer than wide 11 Leaves oblong-ovate or ovate, cordate or subcordate 12 Stipules equalling or exceeding petiole 25. jordanii

12 Stipules usually not more than half as long as petiole

20. canina

11 Leaves ovate-lanceolate or lanceolate, usually not cordate

13 Spur much exceeding calycine appendages 21. lactea

13 Spuronly slightly exceeding calycine appendages

14 Plant glabrous 23. puntila

14 Plant, or at least leaves, shortly pubescent

15 Stems up to 50 cm; stipules equalling or exceeding petiole 24. elatior

15 Stems up to 25 cm; stipules not exceeding petiole,

often only half as long 22. persicifolia

10 Plantwith basal leaf-rosette; leaves usually about as long aswide

16 Stipulesentire; open flowers arising from the base of the rosette

17 Stems glabrous 13. willkommii

17 Stemswith a line of hairs 12. mirabilis

16 Stipules usually dentate or fimbriate; open flowers cauline

18 Calycine appendages 2-3 mm, conspicuous

19 Flowers pale-blue or whitish; stigma hairy 19. sieheana

19 Flowers deep violet; stigma glabrous or papillose

18. riviniana

18 Calycine appendages not more than 1 mm, inconspicuous

20 Stipules narrowly lanceolate, long-fimbriate

15. reichenbachiana

20 Stipules broadly lanceolate to ovate, shortly fimbriate

21 Stems up to 25 cm; spur 4-6 mm 16. tanaitica

21 Stems not more than 10 cm; spur 1-5-4 mm

22 Leaves delicate; petiole glabrous or with scattered hairs 17. mauritii

22 Leaves firm; petiole usually pubescent 14. rupestris

1 Acaulescent,lacking leafy, aerial stems, but sometimes with stolons

23 Stipulessemi-adnateto petiole 24 Leavesdeeplypalmatifid 31. pinnata 24 Leaves simple, not palmatifid

25Leavescordate withshallow sinus;plantwithcreeping rhizome 26. uliginosa

25 Leavescordate with deep sinus; plant without creeping rhizome

26 Sepals obtuse 29. jooi

26 Sepals acute 30. selkirkii

23 Stipules free 27 Sepals acute 28 Leaves acute 12. mirabilis

28 Leaves obtuse 13. willkommii

27 Sepals obtuse 29 Capsule trigonous, explosive; fruiting peduncles erect

30 Leaves in pairs; bracts in upper third of peduncle

28. epipsila

30 Leaves 3 or 4 together; bracts at middle of peduncle

27. palustris

29 Capsule spherical, not explosive; fruiting peduncles procumbent

31 Stolons present

32 Whole plant glabrous

33 Stipules broad, triangular; stolons stout 5. jaubertiana

33 Stipules narrow

34 Stipules lanceolate; stolons short, stout 2. suavis

34 Stipules linear-lanceolate; stolons long, slender

3. alba

32 Plant with hairs on stem, leaves or fruit

35 Stolons short,stout 2. suavis

35 Stolons long,slender

36 Leaves orbicular,obtuse; stipulesbroadlyovate

1. odorata

36 Leaves ovate,acute; stipuleslinear-lanceolate

37 Leaves sparselyhairy; lateralpetalsbearded 3. alba

37 Leaveshispid; lateral petalsbeardless 4. eretica

31 Stolons absent

38 Leaves cordatewithdeepsinus

39 Stipules shortlyfimbriate; flowersnotfragrant 6. hirta

39 Stipules long-fimbriate; flowersfragrant

40 Leaves light green; spurwhitish 7. collina

40 Leaves darkgreen; spurviolet 3. alba

38 Leaves cordatewithshallow sinus,ortruncate

41 Leaves truncateorsubcordate

42 Flowerspaleviolet;capsuleglabrous11. chelmea

42 Flowersdarkviolet;capsulepubescent 8. ambigua

41 Leaves cordatewithshallow sinus

43 Leavesoblong-ovate; sepalsandcapsulepubes­

cent 9. thomasiana

43 Leaves broadlyovate; sepalsandcapsuleglabrous

10. pyrenaica

7 Lateralpetalsdirectedupwards; stylecapitateorbilobedat apex

44 Leavesreniform;stylebilobed at apex 33. biflora

44 Leavesnot reniform;stylecapitateat apex

45 Stems entirelysubterranean

46 Leaves± entire; stipulesovate-orbicular 45. grisebachiana

46 Leavescrenate; stipulesoblongorlanceolate 46. alpina

45 Aerialstems present,thoughsometimesvery short

47 Allleaves entire

48 Annual

49 Plant denselyhairy 83. parvula

49 Plant glabrousorsparselyhairy

50 Flowerslessthan1 cm, lilac-blue 84. heldreichiana

50 Flowers1 cm, yellow 85. mercurii

48 Perennial

51 Spur 5 -10mm; flowers2 cm ormore

52 Leaveslineartooblong-spathulate; flowers yellow

(rarelyviolet) 40. brachyphylla

52 Atleastthelowerleavesbroader; flowerspink or violet

53 Stipules with2 -7basal laciniae 38. valderia

53 Stipules entireorrarelywith1 -2laciniae

54 Spur5 -8mm; petioleslongandslender 36. cenisia

54 Spur 8 -10mm; petiolesshort andstout39. magellensis

51 Spur lessthan5 mm

55 Plantwitha short,densetomentum

56 Upperleavesnarrowerthanlower; stipuleswith3

laciniae 35. diversifolia

56 Upperleavesnotnarrower than lower; stipules entireorwith1 lacinia

57 Spurnotmorethantwice as long as calycine appendages 42.stojanowii

57 Spur 2 -3timesaslongascalycineappendages

43. fragrans

55 Plant glabrousorsparselypubescent

58 Spur scarcelyexceedingcalycineappendages

59 Leavesoblong; flowersusuallyyellow 41. perinensis

59 Leaves ovatetoorbicular; flowersvioletto whitish

60 Petioleslightlylongerthanlamina 34. crassiuscula

60 Petioleat leasttwiceaslongaslamina 45. grisebachiana

58 Spur at leasttwice aslongascalycineappendages

61 Flowersupto2 -5cm; spurslender 37. comollia

61 Flowersc.1 cm; spurstout

62 Leaves ovatetoorbicular,subcordate 47. nummulariifolia

62 Leavesoblong-lineartooblong-ovate, not subcordate

63 Leavesc.1-5 cm,graduallynarrowedtopetiole

43. fragrans 63 Leaves up to 2-5 cm, abruptly contracted into petiole 44. poetica 47 At least the lower leaves crenate or serrulate

64 Annual orbiennial; flowers usually not more than 1-5 cm

65 Corolla equalling or shorter than calyx

66 Flowers 1-1-5 cm

67 Bracts of peduncle concealed by the calycine appendages 87. occulta 67 Bracts of peduncle not concealed 80. arvensis 66 Flowers less than 1 cm

68 Plant glabrous or sparsely hairy 84. heldreichiana 68 Plant densely hairy

69 Hairs short; leaves crenately lobed 81. kitaibeliana 69 Hairs long; leaves almost entire 83. parvula 65 Corolla distinctly exceeding calyx

70 Plant hispid 82. hymettia 70 Plant not hispid(sometimes pubescent below)

71 Leaves almost entire; stipules usually 3-partite

85. mercurii 71 Leaves crenate; stipules divided into more than 3 segments

72 Flowers 1-3-5 cm; spur 3-6-5 mm 78. tricolor 72 Flowers c. 1cm; spur 2-3 mm 86. demetria 64 Perennial;flowersusually1- 5 cmor more

73 Spur 7-5 mm or more

74 Stipules ovate-triangular 63. cornuta 74 Stipules not ovate-triangular

75 Caespitose 59. doerAeri 75 Not caespitose

76 Stipules deeply divided into at least 6 segments

77 Plant hairy

78 Flowers 3-4 cm 50. splendida 78 Flowers 2-3 cm

79 Stipules 7- to 17-partite; spur 5-8 mm

66. elegantula 79 Stipules 3- to 8-partite; spur 8-10 mm

55. pseudogracilis 80 Flowers yellow

80 Flowers violet

81 Plant puberulent 67. athois 81 Plant with patent hairs 75. bubanii 77 Plant glabrous or subglabrous

82 Spur not more than 8 mm 66. elegantula 82 Spur 8-15 mm

83 Lower stipules entire or dentate 48. calcarata 83 Lower stipules 3- to 7-partite 55. pseudogracilis 76 Stipules entire or dentate, or divided into not more than 5 segments

84 Stipules entire or dentate 48. calcarata 84 Stipules, atleast the upper, pinnately divided, with

3-5 segments

85 Plant with slender, creeping rhizomes 57. oreades 85 Plant without slender, creeping rhizomes

86 Plant hairy

87 Upper leaves linear to lanceolate

88 Upperleaves and segments of stipules narrow- linear 49. bertolonii 88 Upper leaves and segments of stipules linearlanceolate to lanceolate 51. aethnensis 87 Upper leaves lanceolate to ovate

89 Flowers yellow 55. pseudogracilis 89 Flowers violet 67. athois 86 Plant glabrous or subglabrous

90 Upper leaves linear to lanceolate, differing greatly from the lower

91 Flowers ± square in face view; petals usually contiguous 49. bertolonii 91 Flowers narrowly rectangular in face view; petals not contiguous 53. Corsica 90 Upper leaves lanceolate to ovate, usually not differing greatly from the lower

92 Leaves slightly fleshy; flowers 3-5 cm; spur

c. 15 mm 54. munbyana

92 Leaves not fleshy; flowers 2-3 cm; spur

8-12 mm

93 Stipules 0-5-1 cm, 3-partite; flowers dark violet 52. nebrodensis 93 Stipules 1-2 cm, 3- to 7-partite; flowers yellow or bluish-violet 55. pseudogracilis 73 Spur 7 mm or less

94 At least the upper leaves linear or linear-lanceolate

95 Lower leaves orbicular

96 Without leafy stolons; flowers 2-2-5 cm 72. dubyana 96 With leafy stolons; flowers 2-5-3-5 cm 73. declinata 95 Lower leaves not orbicular

97 Caespitose; plant usually pubescent, rarely glabrous 60. allchariensis 97 Not caespitose; plant glabrous

98 Flowers 1-5-2 cm; spur 6 mm 71. rhodopeia 98 Flowers 2-5-4 cm; spur 3-4 mm

99 Lower leaves linear-lanceolate 70. beckiana 99 Lower leaves ovate 73. declinata 94 Leaves not linear or linear-lanceolate

100 Stipules not divided, denticulate 62. arsenica 100 Stipules ± deeply divided, or dentate

101 Plant not more than 3 cm

102 Sepals dentate 61. frondosa 102 Sepals entire or serrate 56. eugeniae 101 Plant more than 3 cm

103 Stipules pinnately divided; terminal segment large, usually crenate

104 Sepals ovate-lanceolate or triangular 79. aetolica 104 Sepals lanceolate or linear

105 Flowers 1-1-5 cm, yellow; spur slightly longer than calycine appendages 77. langeana 105 Flowers 1-5-4 cm, violet or yellow; spur up to

3 times as long as calycine appendages

106 Petals as wide as long 56. eugeniae 106 Petals longer than wide 78. tricolor 103 Stipules ± divided but terminal segment not large or crenate

107 Stipules divided to mid-vein or almost to base,

the undivided part not wider than the length of the segments

108 Stems hairy

109 Upper leaves narrowly lanceolate 72. dubyana 109 Upper leaves ovate or oblong

110 Spur 6-7 mm, much longer than calycine appendages 68. gracilis 110 Spur c. 4 mm, not much longer than calycine appendages 76. hispida 108 Stems glabrous or subglabrous

111 Sepals ovate-lanceolate or triangular 79. aetolica 111 Sepals lanceolate or linear

112 Plant with leafy stolons 73. declinata 112 Plant without leafy stolons

113 Caespitose 58. eximia

113 Not caespitose

114 Stipules 6- to 9-partite; spur curved

72. dubyana

114 Stipules 3- to 5-partite; spur straight

74. lutea 107 Stipules not very deeply divided, the undivided part wider than the length of the segments

115 Flowers 3-4 cm; petals almost orbicular

116 Spur stout, not much longer than calycine appendages 57. oreades 116 Spur slender, twice as long as calycine appendages 69. speciosa 115 Flowers usually less than 3 cm; petals ± ovate

117 Spur 3 times as long as calycine appendages

66. elegantula 117 Spur not more than twice as long as calycine appendages

118 Plant hairy; spur twice as long as calycine appendages 64. orphanidis 118 Plant glabrous or slightly hairy; spur equalling or scarcely exceeding calycine appendages 65. dacica Sect , viola (Sect. Nomimium Ging.). Herbaceous. Stipules not leafy. Open flowers blue, violet or white; cleistogamous flowers produced. Style beaked at apex.