Potentina L.

19. Potentina L. a

Perennial, rarely annual or biennial herbs, or small shrubs. Leaves digitate, pinnate or ternate. Flowers solitary or in cymes, (4-)5(-6)-merous. Hypanthium more or less flat, with a central, hemispherical, dry or spongy receptacle; epicalyx present; stamens 10-30; carpels (4-)10-80; style nearly basal, lateral or terminal. Fruit a head of achenes; styles usually not persistent.

Descriptions of leaves and leaflets refer only to the basal and lower cauline leaves.

Many species are cultivated in gardens for ornament. In addition to those native in Europe, the following species from the Himalayas are cultivated and are very locally naturalized: P. atrosanguinea Loddiges ex D. Don , Prodr. FI. Nepal. 232 (1825), densely pubescent, with digitate leaves, 5 leaflets and red or purple petals longer than sepals; P. nepalensis Hooker , Exot. FI. t. 88 (1824), sparsely hairy, with ternate leaves and orangescarlet to red or purple petals longer than the sepals; P. argyrophylla Wallich ex Lehm. , Pugillus 3: 36 (1831), with ternate, silvery-sericeous leaves and yellow petals 10-15 mm.

Interspecific hybridization and apomixis are of common occurrence in Subgen. Potentilla (4-54). Some species or groups of species are known to be complexes composed both of amphimictic, usually diploid, plants and apomictic polyploid plants. The experimental evidence at present available is somewhat fragmentary. 18-20, 22, 43 and 49 are known to be wholly or partially apomictic and morphological evidence suggests that 21, 38-39 and 50 (and possibly others) are of hybrid origin and are therefore likely to be apomictic. Intermediates, presumably of hybrid origin, between any two of 15-51 may occur and be locally common. Some of these appear to reproduce apomictically, and now occur well outside the range of one of the putative parents, e.g. P. subarenaria Borbas ex Zimmeter (probably 49 x 51) in Fennoscandia.

Because of hybridization, and apomixis it is often difficult to classify the material in clear-cut species. As a result of this, occasional individuals may not key out satisfactorily and may have characters which do not fully agree with the descriptions.

Literature: T. Wolf, Biblioth. Bot. (Stuttgart) 71: 1-715 (1908). B. Pawlowski, Fragm. FI. Geobot. 11: 53-91 (1965) (Subgen. Fragariastrum). R. Czapik, Acta Biol. Cracov. (Bot.) 5: 43-61 (1962). A. Müntzing, Hereditas 44: 280-329 (1958), Bot. Not. 111:209-227 (1958). G. L. Smith, New Phytol. 62:264-300 (1963). The last 4 papers deal with apomixis in the genus.

1 Leaves pinnate

2 Petals white or purple

3 Petals purple, shorter than sepals 3. palustris 3 Petals white, longer than sepals 5. rupestris 2 Petals yellow

4 Flowers solitary in the axils of leaves or large bracts

5 Stoloniferous; petals longer than sepals 4. anserina 5 Not stoloniferous; petals shorter than sepals 23. supina I Flowers mostly in cymes; bracts small or 0

6 Shrub; achenes pubescent 1. fruticosa 6 Herbs, sometimes woody at base; achenes glabrous

7 Leafletsentireor 2 - to3- fidat apex 2. bifurca 7 Leafletstoothedor pinnatifid,at leastsome withmore than

3 teeth or lobes

8 Leaflets toothed or pinnatifid about 1-way to the midrib

9 Petals 4-5 mm; calyx accrescent; sepals c. 10 mm in fruit 24. norvegica 9 Petals 5 mm or more; calyx not accrescent; sepals less than 10 mm in fruit

10 Terminal leaflet of lower leaves 20-40 mm wide, larger than the lateral; sepals obtuse 6. geoides 10 Terminal leaflet of lower leaves less than 20 mm wide, about the same size as the laterals; sepals acute

11 Stem and inflorescence tomentose or sericeous, usually eglandular

12 Leaflets 3-5; petals 5-8 mm 8. rubricaulis 12 Leaflets (5—)7— 19; petals 8-10 mm 11. pensylvanica 11 Stem and inflorescence with short, glandular and eglandular hairs and a few setae

13 Leaflets 20-40 mm; petals scarcely longer than sepals 12. longifolia 13 Leaflets 4-25 mm; petals 1^—2 times as long as sepals

14 Lower leaves with 7-12 pairs of leaflets; epicalyxsegments distinctly longer than sepals

13. pimpinelloides 14 Lower leaves with 5-8 pairs of leaflets; epicalyxsegments as long as or slightly longer than sepals 14. visianii 8 Leaflets pinnatisect, divided almost to the midrib into linear or oblong lobes

15 Leaflets 3-5; flowers 1—3(—6) on each stem

16 Petals 3-6 mm, only slightly longer than sepals; stems usually sericeous-villous 7. pulchella 16 Petals 5-8 mm, distinctly longer than sepals; stems patent-pubescent 8. rubricaulis 15 Leaflets 5 or more; flowers usually more than 5 on each stem

17 Sepals as long as or slightly longer than epicalyxsegments; stems and leaves tomentose 9. multifida 17 Sepals about twice as long as epicalyx-segments; stems and leaves densely patent-hirsute

10. eversmanniana 1 Leaves ternate or digitate

18 Petals white, cream or pink

19 Style hairy, at least in the lower half, persistent in fruit

75. saxifraga 19 Style glabrous, or hairy at the extreme base, deciduous

20 Petals with a long claw

21 Leaflets crenate-dentate at least in the apical f, tomentose and without straight hairs 66. speciosa 21 Leaflets toothed only at apex, tomentose but with many straight hairs

22 Achenes pubescent 67. apennina 22 Achenes glabrous 23 Petals purple; leaflets 4-8 mm 68. kionaea 23 Petals white; leaflets 8-20 mm 69. deorum 20 Petals without or with a short claw

24 Leaves ternate, rarely digitate

25 Petals 10-15 mm; stems silvery-grey sericeous 59. nitida 25 Petals less than 10 mm; stems not sericeous

26 Stems 5- to many-flowered, exceeding the leaves; carpels sparsely hairy on the dorsal side, otherwise glabrous 65. granunopetala 26 Stems 1 - to 4-flowered, usually shorter than leaves; carpels pubescent on the ventral side, otherwise glabrous

27 Leaflets crenate-dentate only towards the apex; petals

6-9 mm 71. montana 27 Leaflets serrate almost to the base; petals not more than 7 mm

28 Usually stoloniferous; filaments filiform, glabrous

72. sterilis 28 Not stoloniferous; filaments broad and flat, densely ciliate at least up to the middle

29 Petals shorter than or as long as sepals; stems and pedicels eglandular 73. micrantha 29 Petals longer than sepals; stems and pedicels with some pluricellular glandular hairs 74. carniolica 24 Leavesdigitatewith5 ormoreleaflets

30 Flowers stellate, the sepals and petals patent; petals usually longer than sepals

31 Stems and inflorescence silvery-sericeous

32 Leaves silvery-sericeous above; stems not more than

5 cm, 1- or 2-flowered 59. nitida 32 Leaves glabrous above; stems 10-30 cm, usually many-flowered 60. alchimilloides 31 Stems and inflorescence not sericeous

33 Leaflets silvery-sericeous beneath, glabrous or subglabrous and green above; achenes with a few long hairs at the point of attachment, otherwise glabrous 70. alba 33 Leaflets green or somewhat sericeous, but the two surfaces always ± similar; achenes villous

34 Free part of stipules of the basal leaves ovate or ovate-lanceolate 58. crassinervia 34 Free part of stipules of the basal leaves linear or linear-lanceolate

35 Petals 6-8 mm wide, much longer than sepals; filaments filiform, glabrous 57. clusiana 35 Petals not more than 5 mm wide, slightly longer than sepals; filaments thickened and pubescent at base

36 Stems 5-30 cm, pubescent or villous; epicalyxsegments as long as or slightly longer than sepals 55. caulescens 36 Stems 2-10 cm, densely villous; epicalyxsegments distinctly shorter than sepals

56. petrophila 30 Flowers subcampanulate, the sepals and petals erectopatent; petals shorter than or about equalling sepals

37 Achenes sparsely hairy on the dorsal side, otherwise glabrous; petals about equalling sepals

65. grammopetala 37 Achenes villous; petals shorter than sepals

38 Leaflets grey- or silvery-tomentose or sericeous beneath

39 Stems and petioles with a very short, grey tomentum and with a few long, appressed or erecto-patent hairs 61. valderia 39 Stems and petioles with dense, long, patent hairs

62. haynaldiana 38 Leaflets pubescent and glandular beneath, green, sometimes sericeous when young

40 Leaflets crenate-serrate in the apical epicalyxsegments about as long as sepals 63. doerfleri 40 Leaflets with a few teeth in the apical |; epicalyxsegments longer than sepals 64. nivalis

18 Petalsyellow

41 Leaflets withat leastsomestellateorbranchedhairs beneath

42 Leaflets 5-7, with relatively sparse stellate hairs beneath; stellate hairs with usually 5-10 rays 50. pusilla 42 Leaflets 3-5, with a dense tomentum of stellate hairs beneath; stellate hairs with usually 15-30 rays 51. cinerea 41 Stellate or branched hairs absent

43 Sepals and petals 4, at least in some flowers

44 Sepals and petals almost always 4; carpels 4-8(-20); most leaves with 3 leaflets (but with stipules resembling leaflets) 52. erecta 44 Sepals and petals 4-5; carpels 20-50; some leaves with

4-5 leaflets 53. anglica 43 Sepals and petals 5

45 Flowering stems procumbent, rooting at the nodes; flowers solitary in the axils of leaves 54. reptans 45 Flowering stems usually not rooting at the nodes; flowers usually in terminal cymes

46 Leaflets densely tomentose, villous or sericeous beneath,

the indumentum completely covering the surface of the leaflet

47 Epicalyx-segments up to 2 times as long as sepals, about as wide as sepals at the base 26. astracanica 47 Epicalyx-segments not or only slightly longer than sepals, narrower than sepals at the base

48 Leaflets sericeous or villous beneath, the hairs all

± straight

49 Petals (4-)5-7 mm; epicalyx-segments oblong or oblong-lanceolate, obtuse or subacute 39. nevadensis 49 Petals 12-14 mm; epicalyx-segments linearlanceolate or linear-triangular, long-acuminate

27. detommasii 48 Leaflets tomentose, with most of the hairs crispate

50 Leaflets entire in the basal |

51 Style slightly davate, but often somewhat distorted

22. collina 51 Style conical, tapering towards apex

52 All hairs crispate 18-20. argentea group 52 Some hairs crispate, some long and simple

21. inclinata 50 Leaflets toothed or lobed almost to the base

53 Leaflets at least 3 times as long as wide

21. inclinata 53 Leaflets less than 3 times as long as wide

54 All hairs on petiole crispate; leaflets 3 15. nivea 54 At least some hairs on petiole long and straight;

leaflets 3-5

55 Leaflets with tufts of silky hairs at apex

8. rubricaulis 55 Leaflets without tufts of silky hairs at apex

56 Hairs on petiole all long and straight

16. chamissonis 56 Hairs on petiole both crispate and long and straight 17. hookerana 46 Leaflets green or grey-green beneath, the indumentum not completely covering the surface

57 Basal leaves ternate (rarely a few with 4-5 leaflets)

58 Petals 10 mm or more

59 Anthers less than 1 mm; leaflets with 2-4 pairs of teeth 44. aurea 59 Anthers 1 -1-5 mm; leaflets with 4-11 pairs of teeth

60 Basal leaves pubescent between the main veins beneath 31. grandiflora 60 Basal leaves pubescent only on the main veins beneath 32. montenegrina 58 Petals less than 10 mm

61 Annual or short-lived perennial without or with few non-flowering rosettes; epicalyx-segments longer than sepals in fruit 24. norvegica 61 Perennial with numerous non-flowering rosettes;

epicalyx-segments as long as or shorter than sepals in fruit

62 Petals less than 6 mm 63 Leaflets eglandular, glabrous or sparsely hairy beneath, glabrous above 40. brauniana 63 Leaflets usually glandular, densely hairy beneath, sparsely to densely hairy above

64 Petals 3-5 mm, as long as or only slightly longer than sepals; leaflets of basal leaves with elliptical or oblanceolate, very obtuse teeth 41. frigida 64 Petals c. 5 mm, c. 1 | times as long as sepals; leaflets of basal leaves with triangular-oblong, acute or subobtuse teeth 42. hyparctica 62 Petals 6 mm or more

65 Petals cream or pale yellow, about as long as sepals; sepals linear-lanceolate or lanceolate

65. grammopetala 65 Petals yellow, exceeding sepals; sepals ovate or triangular-ovate

66 Terminal tooth of leaflet always smaller than the adjacent lateral; leaflets with appressed, sericeous hairs on the margin and main veins beneath 44. aurea 66 Terminal tooth of leaflet subequal to the adjacent lateral; leaflets without sericeous hairs

67 Leaflets with triangular-oblong, acute to subobtuse teeth; petals not spotted; stems and leaflets usually glandular 42. hyparctica 67 Leaflets with oblong or elliptical, very obtuse teeth; petals often with an orange spot at the base; stems and leaflets usually eglandular 43. crantzii 57 Basal leaves mostly digitate with 5 or more leaflets

68 Flowering stems terminal; rosettes of leaves absent or few, lateral

69 Petals 4-5 mm; sepals and epicalyx-segments accrescent, 15-20 mm in fruit 25. intermedia 69 Petals 5-14 mm; sepals and epicalyx-segments not markedly accrescent

70 Calyx and leaflets, at least on lower surface, with crispate hairs 21. inclinata 70 Calyx and leaflets without crispate hairs

71 Epicalyx-segments up to 2 times as long as the sepals, about as wide as sepals at the base

26. astracanica 71 Epicalyx-segments shorter than to slightly longer than sepals, narrower than sepals at the base

72 Leaflets with 3-7 teeth at apex; stems with long, simple hairs, without or with very few short hairs 29. hirta 72 Leaflets coarsely toothed or pinnatifid to the base; stems with short glandular or eglandular hairs as well as with long, simple hairs

73 Leaflets villous or sericeous beneath with many, crowded, short eglandular hairs 27. detommasii 73 Leaflets with sparse, short eglandular hairs or with short glandular hairs beneath 28. recta 68 Floweringstems lateral;stockwitha terminalrosette of leaves, the plant often with numerous rosettes of leaves

74 Stipules of cauline leaves adnate to the whole length of the petiole 36. stipularis 74 Stipules of cauline leaves free or adnate only to the base of the petiole

75 Lower surface of leaflets with crispate hairs, usually

± tomentose 22. collina 75 Lower surface of leaflets with ± straight or slightly curved hairs, or glabrous

76 Stipules of basal leaves linear to linear-triangular

49. tabernaemontani 76 Stipules of basal leaves lanceolate to ovate

77 Plant with sessile yellow glands; style papillose at base 46. humifusa 77 Plant eglandular or with glandular hairs; style not papillose at base 78 At least some basal leaves with 6 or more leaflets

79 Epicalyx-segments narrowly linear 47. patula 79 Epicalyx-segments oblong or linear-lanceolate to broadly elliptical or lanceolate

80 Style conical-filiform 81 Leaflets glabrous above; petals c. 6 mm 37. longipes

81 Leaflets hairy above; petals usually more than 6 mm (38-39). chrysantha group

80 Style conical at base, slightly davate at apex 82 Hairs on stems and leaves with a minute tubercle at base 45. heptaphylla

82 Hairs on stems and leaves without a minute tubercle at base 48. australis

78 Basal leaves with not more than 5 leaflets 83 Terminal leaflet with a distinct petiolule 33. umbrosa

83 Terminal leaflet sessile or subsessile 84 Petals 10-15 mm 85 Terminal tooth of leaflet always smaller than the adjacent lateral; style slightly davate

44. aurea

85 Terminal tooth of leaflet subequal to the adjacent lateral; style filiform-cylindrical

86 Cauline stipules acute or acuminate; epicalyx-segments acute 34. delphinensis

86 Cauline stipules obtuse or subacute; epicalyx-segments subobtuse 35. pyrenaica

84 Petals 4—10 mm 87 Hairs on stems and leaves with a minute tubercle at base; hairs mostly patent

88 Petals (6—)7—10 mm; style conical-filiform (38-39). chrysantha group

88 Petals 5-7 mm; style slightly davate

45. heptaphylla

87 Hairs on stems and leaves without a minute tubercle at base; hairs patent or appressed

89 Terminal tooth of leaflet always smaller than adjacent lateral

90 Stems and leaflets variously hairy but never sericeous; style conical-filiform

(38-39). chrysantha group

90 Upper part of stems and inflorescence appressed-sericeous; leaflets with appressed sericeous hairs on the margin and main veins beneath; style slightly davate 44. aurea

89 Terminal tooth of leaflet subequal to the adjacent lateral

91 Style slightly davate; leaflets usually with patent hairs on the margin 43. crantzii

91 Style conical-filiform; leaflets usually with appressed or semipatent hairs on the margin

92 Petals 4-7 mm; leaflets sericeous or sericeous-villous beneath (S. Spain)

30. nevadensis

92 Petals (6-)7-10m m; leaflets usually not sericeous beneath

93 Hairs on stem appressed or subappressed, never glandular

35. pyrenaica

93 Hairs on stem mostly patent or erectopatent, often glandular

(38-39). chrysantha group