Trifolium L.

57. Trifolium L. View in CoL 1

Annual, biennial or perennial herbs, rarely somewhat woody. Leaves 3-foliolate, very rarely digitate with 5(-8) leaflets; leaflets usually toothed. Flowers in heads or short spikes, very rarely solitary. Calyx-teeth equal or unequal; petals persistent or deciduous, adnate to each other and to the staminal tube; stamens diadelphous; all or 5 of the filaments dilated at the apex. Legume included in the calyx or shortly exserted, rarely much exceeding the calyx, indéhiscent or dehiscent by a ventral suture or by an indurated lid. Seeds l-4(-10).

Literature: E. G. Bobrov, Fl. Syst. Pl. Vase. 6: 164-344 (1947). C. Vicioso, Anal. Inst. Bot. Cavanilles 10: 347-398 (1952), 11: 289-383 (1953). R. Hendrych, Presila 28: 403-412 (1956). M. Hossain, Notes Roy. Bot. Gard. Edinb. 23: 387^481 (1961).

A large genus extensively cultivated for fodder. The most important species are 10,14, 29, 30, 62, 63, 88 and 97, but others may be used locally.

1 Some leaves with 5 or more leaflets 2. lupinaster 1 All adult leaves 3-foliolate

2 Calyx with 5(-6) veins; leaves often pinnately 3-foliolate; corolla always persistent and scarious in fruit

3 Calyx-teeth subequal or the 2 upper longer than the rest; corolla before anthesis white or cream; flowers ±umbel'-

late, subtended by membranous bracts; legume 2- to 4- seeded

4 Calyx-teeth subequal, subulate, separated by broad obtuse sinuses 14. hybridum 4 Calyx-teeth unequal, the 2 upper longer than the rest,

narrowly lanceolate, separated by narrow acute sinuses

10. repens 3 Calyx-teeth unequal, the 2 upper shorter than the rest; corolla before anthesis yellow, orange, lilac or violet; flowers ±spicate; bracts represented by a few short, red, evanescent glandular hairs; legume l(-2)-seeded

5 Corolla violet or reddish-violet before anthesis

6 Fruiting heads ovoid, lax, with peduncles exceeding the leaves; corolla 8-10 mm 34. speciosum 6 Fruiting heads subglobose, dense, with peduncles equalling or shorter than the leaves; corolla 4^6 mm 36. lagrangei 5 Corolla yellow, rarely orange or lilac before anthesis

7 Uppermost leaves subopposite; heads solitary, paired or few, pseudoterminal

8 Perennial; corolla 7-9 mm, bright chestnut-brown after anthesis 32. badium 8 Annual or biennial; corolla c. 6 mm, very dark brown after anthesis 33. spadiceum 7 All leaves alternate; heads usually numerous, lateral,

axillary 9 All leaflets of the upper leaves subsessile, their petiolules subequal

10 Fruiting pedicels 2-4 times as long as the upper limb of the calyx-tube 45. Sebastiani 10 Fruiting pedicels not more than 11 times as long as the upper limb of the calyx-tube, usually much shorter

11 Fruiting pedicels 1 -11 times as long as the upper limb of the calyx-tube; corolla 2-3(-4) mm

47. micranthum 11 Fruiting pedicels distinctly shorter than the upper limb of the calyx-tube; corolla 5-8 mm

12 Stipules of the upper leaves lanceolate-ovate, not dilated at the base 42. aureum 12 Stipules of the upper leaves semicordate-ovate, often auriculate

13 Leaflets oblong-ovate or rhombic, widest near the middle 43. velenovskyi 13 Leaflets obovate-cuneate or narrowly ellipticobovate, widest near the apex

14 Stems 20-50 cm; leaflets up to 18 mm, narrowly elliptic-obovate; corolla 5-7 mm 41. patens 14 Stems 5-20 cm; leaflets 8-10 mm, obovatecuneate; corolla 7-8 mm 37. brutium 9 Terminal leaflet of the upper leaves distinctly petiolulate,

its petiolule longer than that of the lateral leaflets

15 Corolla 3-3-5 mm, scarcely sulcate 46. dubium 15 Corolla 4-10 mm (if less, then markedly sulcate)

16 Corolla (3—)4—5(—6) mm; legume 3-6 times as long as the style 44. campestre 16 Corolla (5—)6—10 mm; legume scarcely exceeding the style

17 Peduncles shorter than or equalling the leaves;

pedicels 1 -2 mm, longer than the upper limb of the calyx-tube 35. boissieri 17 Peduncles exceeding the leaves; at least the lower pedicels not longer than the upper limb of the calyx-tube

18 Lower pedicels about as long as the upper limb of the calyx-tube, upper pedicels somewhat longer

40. dolopium 18 All pedicels much shorter than the upper limb of the calyx-tube

19 Corolla 5-7 mm; stems 20-50 cm 41. patens 19 Corolla 7-9 mm; stems 5-20 cm

20 Corolla 8-9 mm; orange before anthesis

39. aurantiacum 20 Corolla 7-8 mm, yellow before anthesis

21 Stipules oblong-lanceolate, not semicordate-

auriculate 38. mesogitanum 21 Stipules semicordate-ovate, often auriculate

37. brutium 2 Calyx with more than 5(—6) veins, usually 10, 20 or more; leaves digitately 3-foliolate; petals deciduous or marcescent, sometimes scarious

22 Flowerssubtendedbysmall,sometimesconnate,bracts; throat of calyx not closed by a ring of hairs or by an annular or bilabiate callosity; legume usually 2- to 8- seeded, included or exserted

23 Calyx-tube not inflatedinfruit

24 Heads 1 - to 6-flowered

25 Corolla 6-8 mm; legume greatly exserted

1. omithopodioides 25 Corolla 12-25 mm; legume not or slightly exserted

26 Peduncles less than 15 mm, usually concealed by the stipules; bracts free; calyx-tube cylindrical

24. uniflorum 26 Peduncles 15-150 mm, evident; bracts connate, forming 1 or 2 minute involucres; calyx-tube campanulate

27 Peduncles 50-150 mm; corolla 18-25 mm 3. alpinum 27 Peduncles 15-25 mm; corolla 12-14 mm 4. pilczii 24 Heads 7- to many-flowered

28 All heads sessile 29 Intemodes 10-80 mm; heads ±remote; corollalonger than the calyx 22. glomeratum 29 Intemodes usually less than 5 mm; heads congested or confluent; corolla shorter than the calyx 23. suffocatum 28 At least some heads with peduncles 5 mm or more

30 Stipules denticulate or fimbriate

31 Veins of the leaflets and stipules ending in glandular teeth; standard slightly exceeding the calyx

5. strictum 31 Veins of the leaflets and stipules not ending in glandular teeth; standard about twice as long as the calyx 6. nervulosum 30 Stipules not denticulate or fimbriate

32 Stems creeping and rooting at the nodes

33 Upper calyx-teeth narrowly lanceolate; leaflets with translucent lateral veins and usually light or dark markings 10. repens 33 Upper calyx-teeth ovate-lanceolate or triangular; leaflets with opaque lateral veins and usually unmarked 11. occidentale 32 Stems not creeping or rooting at the nodes

34 Corolla 18-25 mm; bracts connate, forming 1 or 2 minute involucres 3. alpinum 34 Corolla 5-16 mm; bracts not connate

35 Fruiting pedicels as long as or longer than the calyxtube

36 Perennial

37 Calyx-teeth subulate, separated by broad obtuse sinuses 14. hybridum 37 Calyx-teeth lanceolate or narrowly triangular,

with narrow acute sinuses

38 Pedicels 4-5 x 0-5 mm, strongly thickened in fruit; standard straight 15. bivonae 38 Pedicels 1 -4 x0-1-0-2 mm, scarcely thickened in fruit; standard ± recurved

39 Flowers not or scarcely deflexed after anthesis;

calyx-tube about as wide as long 13. thalii 39 Flowers strongly deflexed after anthesis; calyxtube longer than wide

40 Standard ovate-lanceolate 10. repens 40 Standard broadly ovate or elliptical

12. pallescens 36 Annual

41 All calyx-teeth 2-4 times as long as the tube

42 Heads 20-25 mm wide; corolla 8-11 mm; seeds

2 mm 18. michelianum 42 Heads 10-15 mm wide; corolla 6-8 mm; seeds

1 mm 19. angulatum 41 Upper 2 calyx-teeth equalling or only slightly exceeding the tube

43 Heads 10-20 mm wide; corolla 6-9 mm

17. nigrescens 43 Heads 8-12 mm wide; corolla 4-5 mm

21. cernuum 35 Fruiting pedicels shorter than the calyx-tube

44 Annual

45 Heads 8-11 mm wide, globose; corolla 4-5 mm

20. retusum 45 Heads 15-25 mm wide, hemispherical or cylindrical; corolla 9-12 mm 16. isthmocarpum 44 Perennial

46 Calyx sparsely pubescent, at least at the base of the teeth

47 Heads globose or ovate; corolla 7-9 mm

7. montanum 47 Heads oblong; corolla 10-15 mm 8. ambiguum 46 Calyx glabrous

48 Peduncles 10-30 mm; corolla 5-8 mm; calyxteeth ovate-triangular (Greece) 9. parnassi 48 Peduncles (10-)50-150 mm; corolla 7-12 mm;

calyx-teeth lanceolate to subulate

49 Calyx-tube as wide as long, somewhat inflated in fruit; corolla 6-10 mm 13. thalii

49 Calyx-tube longer than wide, cylindrical; corolla 10-12 mm 15. bivonae

23 Calyx-tube slightly to conspicuously inflated or gibbous in fruit

50 Perennial

51 Calyx-tube in fruit glabrous, ± regular, only the 10 longitudinal veins conspicuous 13. thalii

51 Calyx-tube in fruit pubescent and strongly gibbous above, with numerous longitudinal and transverse veins forming a reticulum

52 Bracts 0-5-1 mm, free 28. physodes

52 Bracts 3-4 mm, ± united below into an irregular involucre 29. fragiferum

50 Annual

53 Fruiting calyx pubescent, tomentose or lanate (sometimes finally glabrescent), adaxially gibbous; bracts inconspicuous and ±concealed; heads lateral

54 Fruiting heads ±pedunculate; calyx pyriform, pubescent to tomentose, finally glabrescent, its 2 upper teeth evident, divergent 30. resupinatum

54 Fruiting heads subsessile; calyx ± globose, lanate, its

2 upper teeth ± concealed 31. tomentosum

53 Fruiting calyx glabrous, inflated ±equally on all sides; bracts prominent, glumaceous, striate; heads pseudoterminal

55 Leaflets broadly obovate-cuneate; corolla slightly exceeding the calyx; bracts shorter than the fruiting calyx-tube 25. spumosum

55 Leaflets (at least the upper) oblong, elliptical or lanceolate, rarely obovate-elliptical or suborbicularcuneate; corolla much exceeding the calyx; bracts about as long as the fruiting calyx-tube

56 Calyx-tube usually much inflated in fruit with 24-35 prominent longitudinal and ± prominent transverse veins 26. vesiculosum

56 Calyx-tube scarcely inflated in fruit without or with

c. 24 weak longitudinal veins and without transverse veins 27. mutabile

22 Flowers ebracteate but heads sometimes involucrate;

throat of the calyx usually ± closed by a ring of hairs or an annular or bilabiate callosity at maturity; legume

l (-2)-seeded, almost always included in the calyx-tube

57 Fertileflowers 2 -12; inner flowers consistingonlyofsterile calyces developing either at or after anthesis

58 Sterile flowers developing after anthesis from a central nodule; fruiting heads appressed to the ground or subterranean 97. subterraneum

58 Sterile flowersdeveloping simultaneously with the fertile ones; fruiting heads aerial

59 Fertile flowers 10-15, in 2 rows; mature heads 20-

25 mm in diameter 98. globosum

59 Fertile flowers 4-6, in 1 row; mature heads 8-15 mm

in diameter 99. pauciflorum

57 Fertileflowersusuallynumerous; sterileflowersabsent

60 Alloratleastsome calycesevidently 20-veined,orthe 20 veins completely obscured by dense sericeous hairs

61 Perennial

62 Apex of stipules pubescent, subulate or narrowly linear, scarious 79. alpestre

62 Apex of stipules glabrous or glabrescent, lanceolate or narrowly triangular, herbaceous

63 Stipules entire, adnate by less than 1 their length to the petiole; leaflets obscurely denticulate 74. medium

63 Stipules often serrate above, adnate by more than | their length to the petiole; leaflets spinosedenticulate 80. rubens

61 Annual

64 Stems less than 4 cm; heads crowded

65 Leaflets deeply emarginate; corolla not exceeding the calyx 70. congestum

65 Leaflets obtuse; corolla about twice as long as the calyx 71. barbeyi

64 Stems 5-40 cm; heads solitary 66 Calyx-tube glabrous or glabrescent; fruiting heads shortly pedunculate, not involucrate 69. lappaceum 66 Calyx-tube hairy; heads sessile, with an involucre formed by the upper stipules

67 Free part of the stipules (except of the uppermost leaves) long, linear-lanceolate, straight; corolla exceeding the calyx 72. hirtum 67 Free part of the stipules (except of the uppermost leaves) short, ovate-lanceolate, often recurved; corolla not exceeding the calyx 73. cherleri 60 Calyx 10-veined, or some calyces with up to 14 veins

68 Perennial

69 Stems1- 5cm; leaflets2-8mm 68. ottonis 69 Stems 5-100 cm; leaflets 10-60 mm

70 Lowest calyx-tooth about 2-3 times as long as the other 4, linear

71 Corolla 20-25 mm; peduncles 40-80 mm

86. pannonicum 71 Corolla 15-20 mm; peduncles not more than 25 mm

85. ochroleucon 70 Calyx-teeth subequal or the lowest not more than 1| times as long as the other four, setaceous, filiform or linear

72 Upper internodes with patent hairs

73 Calyx-tube glabrous

74 Corolla reddish-purple; upper stipules lanceolate

74. medium 74 Corolla cream; upper stipules ovate-lanceolate

78. pignantii 73 Calyx-tube hairy

75 Stipules of the middle cauline leaves abruptly contracted into a setaceous arista; heads sessile, involucrate 63. pratense 75 Stipules of the middle cauline leaves with a triangular-lanceolate, acuminate apex; heads often shortly pedunculate 66. noricum 72 Upper intemodes with appressed hairs, or glabrous

76 Stems 5-8 cm; stipules with an oblong, obtuse apex

67. wettsteinii 76 Stems usually more than 10 cm; stipules acute

77 Stipules of the middle cauline leaves abruptly contracted into a setaceous arista 63. pratense 77 Stipules of the middle cauline leaves with a linear, lanceolate or ovate, ± herbaceous apex

78 Petioles united along their length to the lower part of the stipules

79 Leaflets linear-oblong; calyx-tube densely pubescent 76. patulum 79 Leaflets obovate-cuneate; calyx-tube glabrous

77. velebiticum 78 Petioles united along only part of their length to the stipules

80 Calyx-tube glabrous or glabrescent 74. medium 80 Calyx-tube persistently hairy

81 Calyx-teeth filiform, all of them longer than the tube; corolla pink

75. heldreichianum 81 Calyx-teeth lanceolate-subulate, ± herbaceous,

the upper 4 teeth equalling or shorter than the calyx-tube; corolla yellowish-white,

rarely pink

82 Leaflets not emarginate; lowest calyx-tooth usually distinctly longer than the tube

85. ochroleucon 82 Leaflets deeply emarginate; lowest calyxtooth scarcely longer than the tube

87. canescens 68 Annual

83 Heads sessile, axillary or terminal, involucrate

84 Heads few-flowered, scarcely exceeding the subtending stipules; lowest calyx-tooth shorter than the tube 51. saxatile 84 Heads many-flowered, much exceeding the subtending stipules; lowest calyx-tooth as long as or longer than the tube

85 All leavesalternate

86 Lateral veins of the leaflets ± straight

87 Corolla not or scarcely exceeding the lowest calyxtooth

88 Calyx-teeth subequal, all longer than the tube,

divergent in fruit 56. gemellum 88 Calyx-teeth unequal, only the lowest equalling or slightly exceeding the tube, connivent or somewhat divergent in fruit

89 Fruiting calyx readily abscissing, with ± inflated tube and erecto-patent teeth 48. striatum 89 Fruiting calyx not readily abscissing, tube not inflated, teeth straight or connivent 52. bocconei 87 Corolla exceeding the lowest calyx-tooth

90 Corolla twice as long as the calyx; upper leaflets linear 53. tenuifolium 90 Corolla 11 times as long as the calyx; upper leaflets narrowly oblong to obcordate-cuneate,

deeply emarginate 54. trichopterum 86 Lateralveins of the leafletsrecurved, often± thickened towards the margins

91 Corolla 4-5 mm, equalling or slightly exceeding the calyx; axillary heads numerous 58. scabrum 91 Corolla 8-10 mm, twice as long as the calyx; axillary heads few 59. dalmaticum 85 At least the two uppermost leaves opposite

96. clypeatum 92 Calyx-teethtriangular-lanceolate(- acuminate)or subulate from an expanded triangular base, spreading or recurved in fruit

93 Corolla much shorter than the calyx; calyx-teeth subequal, up to 4 times as long as the tube

61. dasyurum 93 Corolla nearly equalling or exceeding the calyx; calyx-teeth unequal or subequal, not more than twice as long as the tube and usually less

94 Throat of the calyx closed with a ring of hairs

95 Calyx-teeth triangular-lanceolate, dilated at the base, as long as or shorter than the tube

55. phleoides 95 Calyx-teeth lanceolate-setaceous, scarcely dilated at the base, longer than the tube

56. gemellum 94 Throat of the calyx closed by a bilabiate callosity, leaving only a narrow vertical slit

96 Calyx-tube campanulate, glabrous or sparsely hairy above; leaflets 10-20 mm 93. squamosum 96 Calyx-tube ovoid, densely hairy; leaflets

20-40(-70) mm 94. squarrosum 92 Calyx-teethsubulate,setaceousorfiliform,

± straight and erect in fruit

97 Corolla whitish or pink, much exceeding the calyx; calyx-teeth 1-1| times as long as the tube

64. pallidum 97 Corolla reddish-purple, not or scarcely exceeding the calyx; calyx-teeth twice as long as the tube

. 65. diffusum 83 Headspedunculate,terminaloraxillary

98 Upper leaves alternate

99 Leaflets of upper leaves lanceolate, linear or linearoblong

100 Heads 10-25 mm, usually numerous; calyx-throat not closed by a bilabiate callosity

101 Calyx-teeth triangular-lanceolate, dilated at the base, sparsely ciliate or glabrescent 55. phleoides 101 Calyx-teeth setaceous, usually densely pubescent or villous

102 Corolla much shorter than the calyx 49. arvense 102 Corolla equalling or longer than the calyx

50. alfine 100 Heads 20-110 mm, one or few, usually terminal; calyx-throat at maturity narrowed to a vertical slit by a bilabiate callosity 103 Corolla 10-12 mm, not or scarcely exceeding the calyx 81. angustifolium 103 Corolla 13-25 mm, much exceeding the calyx 104 Corolla 16-25 mm; stem robust, little branched 82. purpureum 104 Corolla 13-15 mm; stems weak and diffusely branched 83. desvauxii 99 Leaflets of upper leaves obovate-cuneate or obcordate 105 Heads capitate, ±globose in fruit; stipules denticulate 60. stellatum 105 Heads spicate, oblong, cylindrical or conical in fruit; stipules entire or obscurely dentate 106 Corolla much shorter than the calyx; calyx-tube obconical or campanulate; stipules lanceolate, entire 57. ligusticum 106 Corolla equalling or exceeding the calyx; calyxtube ovoid or globose; stipules ovate, at least at the apex, entire or obscurely dentate or angled 107 Calyx-teeth unequal, the 4 upper ones shorter than the tube, all with long patent hairs 84. smyrnaeum 107 Calyx-teeth subequal, all as long as or longer than the tube, with erecto-patent hairs 62. incamatum 98 At least the two uppermost leaves opposite 108 Corolla 20-25 mm; calyx-teeth broadly ovatetriangular, with many veins. 108 Corolla less than 20 mm; calyx-teeth linearsubulate to ovate-lanceolate, with 1-3 veins 109 Corolla much shorter than the calyx; calyx-teeth subequal, up to 4 times as long as the tube 61. dasyurum 109 Corolla equalling or exceeding the calyx; calyxteeth unequal or subequal, the lowest one not more than twice as long as the tube 110 Leaflets up to 60x 4-5 mm, linear-oblong, acute 91. latinum 110 Leaflets 8-40(-70) x 4-15 mm, relatively shorter and broader, obtuse 111 Legume exserted slightly from the mouth of the calyx-tube 112 Calyx-teeth spinescent in fruit, the lowest one 3-veined, at least at the base 88. alexandrinum 112 Calyx-teeth scarcely spinescent in fruit, the lowest one 1-veined 89. apertum 111 Legume not exserted, concealed by the closed bilabiate callosity at the mouth of the calyxtube 113 Calyx-teeth subequal 114 Calyx-teeth ovate-lanceolate, each with 3-5 veins; heads 20-35 mm, ovate, shortly pedunculate 95. obscurum 114 Calyx-teeth lanceolate, each with 3 veins; heads 10-15 mm, globose; peduncles 30- 120 mm 92. leucanthum 113 Calyx-teeth unequal 115 Calyx-teeth 1 -veined, or 3-veined only at the base 90. echinatum 115 Calyx-teeth distinctly 3-veined to the middle or above 116 Calyx-tube campanulate, glabrous or sparsely hairy above; leaflets 10-20 mm 93. squamosum 116 Calyx-tube ovoid, densely hairy; leaflets 20-40(-70) mm 94. squarrosum